Introduction

Cortisol

Electromyographic (EMG) Activity

Cardiovascular Changes, Oxygenation and Energy Expenditure

Hypertrophy

Strength

Max Strength

Power

Comparing Short and Long Rest Between Set Durations

Comparing Smaller Differences in Rest Between Set Durations

Details: Strength, Gender, and Age

Research Summary

The Most Important Findings from this Review? Rest Between Sets Determined by Volume

Statistically Insignificant Differences

Self-Selected Rest Between Set Durations

Heart Rate Based Rest Between Set Duration

Incremental Increase in Duration with Successive Sets

Rest Between Reps Compared to Conventional Rest Between Sets

How Much Rest Between Reps

Compared to Other Protocols

Frequent Short Rest (Continuous)

Comparing Circuit Training and Conventional Strength Training

Testosterone

Comparison: Despite Higher Peak and Average Heart Rates

Comparing Rest Between Exercises

Growth Hormone

Insulin-like Growth Factor 1 (IGF-1) a.k.a  Somatomedin C (SM-C)

Protein Synthesis

Lactate

Creatine Kinase

Immune System and Inflammatory Markers

Acute Variables: Rest Between Sets

NASM

ACSM

AFAA

CanFitPro

PTAGlobal

ISSA

REPSI

PACE

WITS

AUSREPS

TPTA

NYPT

AOTA

This course discusses <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> rest between sets (a.k.a. rest period, rest interval, rest time, inter-set rest interval, rest between exercises), as well as strategies including rest between reps (a.k.a. intra-set rest, cluster sets, rest redistribution). This course details the <a id="evidence-based-practice" data-tip="1538" target="_blank" href="/glossary-term/evidence-based-practice" class="glossary">evidence-based</a> <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> rest between reps recommendations for <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> endurance, <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> hypertrophy (<a id="hypertophy" data-tip="1233" target="_blank" href="/glossary-term/hypertophy" class="glossary">muscle growth</a>), strength training, <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, athletic performance, functional training, and corrective exercise. The topics discussed in this course include the effects of rest periods on <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> adaptations, short-term and long-term <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a> concentrations, post-exercise protein synthesis, <a id="hypertophy" data-tip="1233" target="_blank" href="/glossary-term/hypertophy" class="glossary">muscle growth</a>, <a id="muscle-cell" data-tip="1377" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle fiber</a> type proportions, EMG activity, fatigue, rate of force development, <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> strength, and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> performance.&#xA0;
Some findings from the included systematic review resulted in counter-intuitive, or at least less conventional recommendations. For example, the most important finding from our systematic review is that recommendations for rest between set durations should be based on sets/exercise (volume), and not load or training goal. General recommendations include moderate (2 min) rest between sets if performing 2 sets/exercise, long rest (3 min) if performing 3 sets/exercise, and very long rest (&gt; 4 min) if performing 4 sets or more/exercise. Additionally, based on all performance measures, circuit training with 30-60 seconds between exercises is as effective as conventional training but may decrease session lengths by 40-60%, especially when longer rest between sets of the same exercise is adopted.&#xA0;
Movement professionals (personal trainers, fitness instructors, physical therapists, athletic trainers, massage therapists, chiropractors, occupational therapists, etc.) should consider acute variables essential knowledge for <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> exercise programming, and rest between sets is one of those acute variables. This course is part of our continued effort to optimize &#x201C;acute variable&#x201D; recommendations.
<h3>Additional Courses:</h3>
<ul>
 <li><a href="https://brookbushinstitute.com/courses/acute-variables-repetition-tempo">Acute Variables: Repetition Tempo</a></li>
 <li><a href="https://brookbushinstitute.com/courses/acute-variables-repetition-range">Acute Variables: Repetition Range</a></li>
 <li><a href="https://brookbushinstitute.com/courses/acute-variables-circuit-training">Acute Variables: Circuit Training</a></li>
</ul>
<h3>Recommendations:</h3>
General&#xA0;
<ul>
 <li>Long (3 min) rest between set durations</li>
</ul>
Specific
<ul>
 <li>2 sets/exercise: Moderate (2 min)</li>
 <li>3 sets/exercise: Long (3 min)</li>
 <li>4 or more sets/exercise: Long (3 min) or very long (&gt; 3 min)</li>
 <li>Alternative: Circuit training with short (1 min) rest between exercises</li>
 <li>Additional Strategy for Power: Inter-set rest of 10 - 20 seconds (sec)</li>
</ul>
Inter-set Rest Periods (Rest Between Reps):&#xA0;Inter-set rest periods of up to 20 seconds may be beneficial for&#xA0;maintaining average and peak velocity/rep during the second half of sets. This strategy may be particularly beneficial for optimizing <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> (high-velocity) training.
<ul>
 <li>Inter-set Rest Period Example:
 <ul>
 <li>Set 1: Box Jumps 5 reps, 10-sec rest, 5 reps</li>
 <li>3 min rest between sets</li>
 <li>Set 2: Box Jumps 5 reps, 12-sec rest, 5 reps</li>
 <li>3 min rest between sets</li>
 <li>Repeat for the desired number of sets</li>
 </ul>
 </li>
</ul>
<img alt="The dumbbell bench press exercise targeting the upper body muscles" title="Dr. Brent Brookbush cues Melissa through multi-planer dumbbell press on bench" src="https://www.datocms-assets.com/25800/1632846046-dumbbell-press.jpg">

Course Description: Rest Between Sets

Acute Variables: Rest Between Sets Video

<h2>Rest Between Sets Recommendations</h2>
General Recommendation: 
<ul>
 <li>Long (3 min) rest between set durations</li>
</ul>
Specific Recommendations:
<ul>
 <li>2 sets/exercise: Moderate (2 min)</li>
 <li>3 sets/exercise: Long (3 min)</li>
 <li>4 or more sets/exercise: Long (3 min) or very long (&gt; 3 min)</li>
 <li>Alternative: Circuit training with short (1 min) rest between exercises</li>
 <li>Additional Strategy for Power:&#xA0;Inter-set rest of 10 - 20 seconds (sec)</li>
</ul>

<h2>General Guidelines and Recommendations</h2>
Long Rest Between Sets: Long (3 min) rest between set durations may significantly improve performance during additional sets (all sets after set 1), including the ability to maintain the number of repetitions (reps)/set, peak, and average force/rep, peak and average velocity/rep, and <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> kinematics (<a id="posture" data-tip="1660" target="_blank" href="/glossary-term/posture" class="glossary">form</a>). The resulting increase in volume (reps/set) may be beneficial for all strength goals, and the maintenance of force/velocity and kinematics may be particularly beneficial for max strength and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> goals. Research has demonstrated that rest between set duration has little if any, effect on outcomes when routines are work/volume matched. This implies that attaining the benefits from longer rest between set durations is due largely to the resulting increase in reps/set and exercise volume; and further, that attaining these benefits may require that sessions include reps until failure/set with similar or additional sets/exercise.
Volume-based Recommendations: Perhaps the most important finding of this review is that r<span style="background-color: transparent; font-family: inherit; font-size: inherit; font-style: inherit; font-variant-ligatures: inherit; font-variant-caps: inherit; font-weight: inherit; letter-spacing: 0px;">est between set durations should be based on sets/exercise (volume), and not load or training goal. <span style="background-color: transparent; font-family: inherit; font-size: inherit; font-style: inherit; font-variant-ligatures: inherit; font-variant-caps: inherit; font-weight: inherit; letter-spacing: 0px;">General recommendations include moderate (2 min) rest between sets if performing 2 sets/exercise, long rest (3 min) if performing 3 sets/exercise, and very long rest (&gt; 4 min) if performing 4 sets or more/exercise. Further, longer rest between set durations may have a larger influence on strength endurance training (high rep; 12 - 20 reps) than maximum strength and <a id="power" data-tip="1399" target="_blank" href="https://brookbushinstitute.com/glossary-term/power" class="glossary" rel="noopener">power</a> training (low reps; 1- 6 reps). It may be reasonable to conclude that very long (&gt; 3 min) rest between set durations is only necessary when performing 3 or more high rep sets (&gt; 15 reps), and that no additional benefit will be attained for rest between set durations longer than 2 minutes during very high-intensity training (&lt; 6 reps/set). It is likely more accurate to think of rest between sets in terms of work/rest ratios; however, for practical purposes, the rest between set durations recommended below will result in the same outcomes.
Circuit Training: Circuit training is an effective option for countering the increase in session time that would result from increasing rest between set durations. Research demonstrates that conventional and circuit protocols of strength training are likely to result in similar reps/set, power/rep, exercise volumes, rates of perceived exertion, and energy consumption; despite circuit training resulting in higher peak and average heart rates/session. Further, circuit training is likely to result in similar improvements in lean body mass, maximum strength, <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, agility, and cardiovascular performance. Increasing rest between exercises up to 1 minute (e.g. 30 sec vs. 1 min) may improve performance; however, it is unlikely that longer rest (&gt; 1 min) will result in additional benefits.
Inter-set Rest Periods (Rest Between Reps):&#xA0;Inter-set rest periods of up to 20 seconds may be beneficial for&#xA0;maintaining average and peak velocity/rep during the second half of sets. This strategy may be particularly beneficial for optimizing <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> (high-velocity) training.
<ul>
 <li>Inter-set Rest Period Example:
 <ul>
 <li>Set 1: Box Jumps 5 reps, 10-sec rest, 5 reps</li>
 <li>3 min rest between sets</li>
 <li>Set 2: Box Jumps 5 reps, 12-sec rest, 5 reps</li>
 <li>3 min rest between sets</li>
 <li>Repeat for the desired number of sets</li>
 </ul>
 </li>
</ul>
<img title="Dr. Brent Brookbush demonstrating a box jump exercise with a client" src="https://www.datocms-assets.com/25800/1649512741-boxjump-1.jpeg" alt="A box jump for lower body power production">
<h2>Definitions and Quick Guides:</h2>
<h3>Rest Between Set Durations:</h3>
<ul>
 <li>Short: 1 minute (min) or less</li>
 <li>Moderate:&#xA0;More than 1 min, but less than 3 min</li>
 <li>Long: 3 min</li>
 <li>Very Long: More than 3 minutes</li>
</ul>
<h3></h3>
<h3>Special Use of the Terms &quot;Work&quot; and &quot;Volume&quot;</h3>
It is necessary to differentiate between &quot;load x reps&quot; and &quot;load x time under tension&quot; to develop accurate conclusions from training and rehabilitation research. Consider these two examples of identical work with volumes that differ by 100%: 10 reps/10kg/1:1:1 tempo, or 10 reps/10kg/3:1:2 tempo. The following definitions of &quot;work&quot; and &quot;volume&quot; are used throughout this course to aid in differentiating these terms.&#xA0;
<ul>
 <li>Work may be defined as &quot;force x distance&quot;; and was used to convey &quot;load x reps&quot;.</li>
 <li>Volume may be defined as &quot;load x time under tension&quot;, and was used to convey the total amount of time that work was performed on a load.</li>
</ul>
&#xA0;
<h3>Physiology and Function</h3>
<ul>
 <li>Anabolic Hormones: Hormones that may stimulate the growth of <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> tissue.
 <ul>
 <li>Testosterone</li>
 <li>Growth Hormone</li>
 <li>Insulin-like growth factor 1 (IGF - 1)</li>
 </ul>
 </li>
 <li>Protein Synthesis: May be an indicator of an increase in the processes of <a id="hypertophy" data-tip="1233" target="_blank" href="/glossary-term/hypertophy" class="glossary">muscle growth</a> (hypertrophy).</li>
 <li>Lactate: The elevation of serum lactate concentrations may be an indicator of increased physical exertion and reliance on anaerobic metabolism.</li>
 <li>Creatine Kinase:&#xA0;An indicator of the amount of tissue damage.</li>
 <li>Leukocytes, Monocytes, and Lymphocytes: Indicators of altered immune and inflammatory function.</li>
 <li>Cortisol: A marker of physical and psychological stress.</li>
</ul>

Systematic Review: Hormones, Immune Response and Metabolism

<h3>Volume</h3>
Studies have compared various rest between set durations and the effect they have on post-exercise serum concentrations of testosterone.&#xA0;Mohamad-Panahi et al. compared 17 male cadet wrestlers (16.7 &#xB1; 0.6 yr) performing moderate (1.5 min.) or long (4-min.) rest between sets during bench press for 4 sets, with 60% of 1-RM, and repetitions performed until failure. Longer rest between sets resulted in a significant increase in reps/set and exercise volume, and immediate post-exercise serum concentrations of testosterone increased following the long, but not the short, rest between sets protocol, and&#xA0;cortisol significantly decreased following both protocols (1).&#xA0;Rahimi et al. compared 10 experienced resistance-trained men (20.37 &#xB1; 2.24 years) performing either short (1 min) or moderate (1.5 min and 2 min) rest between sets during a routine of squats and bench press, for 4 sets/exercise, 85% of 1-RM loads, reps to failure/set, with a moderate tempo (3:0:1). The findings demonstrated that training volume was significantly higher following longer rest between sets, post-exercise serum concentrations of testosterone were highest following the longest rest between sets (2 min) protocol, growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a> was highest following shorter rest between sets protocol, and lactate concentrations were similar for all groups (2). Agostinete et al. compared 8 physically active men (23.5 &#xB1; 3.1) performing short (30 sec.) rest between sets, moderate (90 sec.) rest between sets, or a combination of the short rest with the same number of reps performed with moderate rest (achieved by adding sets). The routine included squats, bench press, and T-bar rows, for 4 sets/exercise (except the combination protocol), with 70% of 1-RM loads, reps until failure/set, and a moderate tempo (1:1:1). The findings demonstrated that the moderate (longer) rest between sets protocols resulted in a significant increase in reps/set and exercise volume, and post-exercise serum concentrations of testosterone were higher for the moderate rest protocols and highest for the combination protocol (3). These studies imply that longer duration rest between sets results in higher concentrations of post-exercise serum testosterone; however, these studies also include protocols with reps performed until failure/set. The combination of longer duration rest between sets, and reps until failure/set, results in significant increases in exercise volume.&#xA0;
<h3>Work-matched</h3>
Two studies with protocols that include similar total work/volume, and varying durations of rest between sets, demonstrate similar increases in post-exercise serum concentrations of testosterone. Abbasi et al. compared 16 resistance trained men performing either short (30 sec) or moderate (2 min) rest between sets. All participants performed a lower body resistance training program (hamstring with machine, squat, deadlift and leg press), using the same protocol the first 2 weeks, including moderate (2 min) rest between sets, 3 sets/exercise, and 10-12 RM/set. During the following 6 weeks participants were divided into short (30 sec) and moderate (2 min) rest between sets groups, performing 4 sets/exercise, with 8-10 RM/set. The findings demonstrated that post-exercise serum concentrations of testosterone and cortisol (and testosterone/cortisol ratio) were similar for both groups (4). Ahtiainen et al. compared 13 recreationally resistance trained men (28.7&#xA0;&#xB1; 6.2 years) with a cross-over study of two work-matched routines; each routine was performed for 3 months and the order of the two routines was assigned randomly. The first routine was performed with moderate (2 min) rest between sets during 5 sets of leg press, 4 sets of squats, and leg extensions, with 10RM/set (lighter loads), and the second routine was performed with long (5 min.) rest between sets during 4 sets of leg press, 3 sets of squats and leg extensions with 10RM/set (heavier loads). The findings demonstrated that both routines resulted in similar changes in strength, <a href="https://brookbushinstitute.com/article/quadriceps-vastus-muscles" target="_blank" rel="noopener">quadriceps</a> cross-sectional area (CSA), and post-exercise serum concentrations of testosterone (increase) and cortisol (decrease) (5).&#xA0;Although the protocols in the study by Abbasi et al. allowed for different loads, it is likely that the volume of exercise was more similar than protocols used in studies that allowed for reps performed until failure/set. These studies demonstrate that&#xA0;when comparing routines with similar total work/volume, increases in post-exercise serum testosterone are also similar.
<h3>Timing of Testing</h3>
Some studies have demonstrated differences in serum concentrations of testosterone following different rest between set durations; however, it is likely that these differences are related to the timing of testing. Scudese (2016) et al. compared 10 resistance-trained men (age: 25.2 &#xB1; 5.6 years) performing short (1 min) or long (3 min) rest between set durations during a bench press routine of 5 sets/session, 3 reps/set, 85% of 1 RM loads, and no attempt to control repetition speed. The findings demonstrated that post-exercise serum concentrations were significantly elevated at 0 and 15 min following the short rest between sets protocol, and 15 and 30 minutes following the long rest between sets protocol (6).&#xA0;Kraemer et al. (1989, 1990) compared 9 recreationally resistance-trained men (age: 24.66 &#xB1; 4.27 years) performing short (1 min) and long (3 min) rest between set durations, and moderate (10RM x 3 sets/exercise) and heavy (5 RM x 3 or 5 sets/exercise) loads, on 4 non-consecutive days, with a &quot;typical body building&quot; routine of 8 exercises (bench press, double leg extension, military press, bent leg incline sit-ups, seated rows, lat pull down, arm curls, leg press). The findings demonstrated that all&#xA0;protocols resulted in similar total increases in serum testosterone&#xA0;concentrations; however, different routines resulted in elevations and peaks at different time points. For example, when short and long rest periods were compared during the heavy protocol, longer rest between sets resulted in lower testosterone concentrations when blood was <a id="drawing-in" data-tip="1583" target="_blank" href="/glossary-term/drawing-in" class="glossary">drawn in</a> the middle of the routine, but higher concentrations when blood was drawn 30-min post exercise (7 ,8). Another study by,&#xA0;Kraemer (1991) et al. used the same methodology to compare 16 recreationally weight-trained men and women (age: 8 males, 24.7 &#xB1; 4.5; 8 females, 23.1 &#xB1; 3.3 years), demonstrating similar levels and timing of post-exercise serum concentrations of testosterone; and further, that males exhibit significantly larger elevations in testosterone when compared to females (9).&#xA0;These studies imply that longer rest between sets may result in slower increases in post-exercise serum testosterone concentrations; however, it is likely that short and long rest between set durations result in similar total concentrations. The different rates of increase may imply that research studies should incorporate multiple blood draws at different time points.&#xA0;Additionally, these studies imply that&#xA0;men exhibit much larger exercise induced elevations in post-exercise serum concentrations of testosterone when compared to women.&#xA0;
<h3>Adaptation</h3>
Last, a study by Buresh et al. may suggest that the differences in post-exercise serum testosterone concentrations, resulting from different rest between set durations, are short-term. Buresh et al. compared 12 resistance-trained men (24.8 &#xB1; 5.9 years) performing either short (1 min) or long (2.5 min) rest between sets during a 2 day split-routine for 10 weeks, 4 sessions (2 days per split)/week, 2-3 sets/exercise, 10 reps/set, with a load that resulted in failure in less than 10 reps during the 3rd set. The day-1 split consisted of exercises for the lower extremities, shoulders, and abdominal muscles, and the day-2 split consisted of exercises for the chest, back, and upper extremities. The findings demonstrated that initial post-exercise serum concentrations of testosterone and cortisol were significantly higher following the short rest between sets protocol; however, the differences diminished and were not statistically significant by the end of the 10 week training period. Additionally, thigh CSA increased similarly for both groups, but arm cross-sectional area (CSA) increased more following the longer rest period protocol (10). This study may imply that within 10 weeks of training, adaptation to different rest between set durations may result in similar elevations in post-exercise serum concentrations of testosterone; and further, hypertrophy (long-term outcomes) may not be correlated with initial differences.

<h3>Similar Outcomes</h3>
Several studies have compared serum concentrations of growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a> following exercise routines with different rest between set durations. As mentioned above,&#xA0;Scudese (2016) et al. compared 10 resistance-trained men (age: 25.2 &#xB1; 5.6 years)&#xA0;performing short (1 min) or long (3 min) rest between sets during a bench press routine of 5 sets/session, 3 reps/set, 85% of 1 RM loads, and no attempt to control repetition speed. The findings demonstrated that post-exercise serum concentration of growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a> did not change following either protocol (6). Fink et al. compared 14 young athletes (age: 18&#x2013;22 years) who had not participated in regular resistance training for at least 2 years, performing short (30 sec) or moderate (2.5 min) rest between sets. The routine included bench press and squats for 8 weeks, 2x/week, 4 sets/exercise, reps until failure/set, with 40% of 1RM, and a moderate rep tempo (2:0:1). Significant and similar increases in growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a> were noted after a single session, despite longer rest periods resulting in significantly more reps performed during sets 2-4. Additionally, a trend toward larger increases in strength and CSA were noted following longer rest periods; however, differences between groups did not reach statistical significance (11). These studies imply that rest between sets does not have a significant effect on post-exercise serum concentrations of growth hormone; however, the design of these studies implies additional research should be considered. Specifically, two issues that deserve further consideration are the relatively low volume of exercise (5 sets of 1 exercise) in the study by Scudese et al. (6), and the study by Fink et al. (11) may have compared post-exercise serum concentrations following sufficient time for adaptation to differences in rest between set durations (similar to the study by Buresh et al. (10)).&#xA0;
<h3>Shorter Rest Between Sets</h3>
Additional studies suggest that shorter rest between set durations may have a significant influence on serum concentrations of growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a>. Bottaro et al. compared 12 healthy trained females (26.83 &#xB1; 3.93 years) performing either short (30 sec and 1 min) or moderate (2 min) rest between sets during a routine of 4 lower body exercises (knee extensions, leg press, knee flexions, and hack squats), 3 sets/exercise, reps until failure/set, with 10-RM loads. The findings demonstrated that post-exercise serum concentrations of growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a> were highest following short (30 sec) rest periods, and similar following 1 and 2 min rest between sets (12). Boroujerdi et al. compared 10 recreationally resistance-trained men (22 &#xB1; 2 years) performing short (1 min.) or long (3 min.) rest between sets during a routine of bench press and squats for 5 sets/exercise, and 10 RM/set. The findings demonstrated that post-exercise serum concentrations of growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a> and lactate were significantly higher following the short rest between sets protocols (13). These studies suggest post-exercise serum concentrations of growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a>, following a single session, increase more with shorter rest between sets. These findings contradict the findings of Scudese et al. (6) mentioned above, which may imply that the length of rest between set durations has an effect on post-exercise serum concentrations of growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a> when volume is sufficient; for example, at least 2 compound exercises performed for 3 sets/exercise.
<h3>Volume</h3>
Additional studies suggest that both shorter rest between sets, and increases in exercise volume, may significantly elevate serum concentrations of growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a>. As mentioned above, a series of studies by Kraemer et al. (1989, 1990, 1991, 1993) compared resistance-trained men and women while performing short (1 min) and long (3 min) rest between sets, moderate load/high volume (10RM x 3 sets/exercise) and heavy load/low volume (5RM x 3 or 5 sets/exercise) protocols, on 4 non-consecutive days, during a typical &quot;bodybuilding&quot; routine of 8 exercises (bench press, double leg extensions, military press, bent leg incline sit-ups, seated rows, lat pull-downs, arm curls, and leg press). The findings demonstrated that both men and women exhibited increases in serum growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a> with shorter rest periods and larger volumes of exercise. This trend was still evident when comparing moderate and heavier loads, and similar for both men and women (7-9, 14). These studies suggest that shorter rest between sets and increases in exercise volume (regardless of load) significantly increase post-exercise serum concentrations of growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a>.

Several of the studies have investigated the effects of rest between set duration on post-exercise serum concentrations of IGF-1. A series of studies by Kraemer et al. (1989, 1990, 1991, 1993) compared resistance-trained men and women, performing short (1 min) or long (3 min) rest between sets, with moderate load/high volume (10RM x 3 sets/exercise) or heavy load/low volume (5RM x 3 or 5 sets/exercise) protocols. The findings demonstrated that post-exercise serum concentrations of IGF-1 varied significantly with no attributable correlation to protocol or gender (7-9, 14). As mentioned above, Rahimi et al. compared&#xA0;10 resistance-trained men (20.37 &#xB1; 2.24 years) performing either short (1 min) or moderate (1.5 min and 2 min) rest between sets during a routine of squats and bench press, for 4 sets/exercise, 85% of 1-RM loads, reps to failure/set, with a moderate tempo (3:0:1). The&#xA0;IGF-1 findings were reported in an additional publication, noting that the post-exercise serum concentrations of IGF-1 were similarly elevated for all groups (15).&#xA0;In another study mentioned above, Boroujerdi et al. compared 10 recreationally resistance-trained men (22 &#xB1; 2 years) performing short (1 min) or long (3 min) rest between sets during a routine of bench press and squats for 5 sets/exercise, 10 RM/set. The findings demonstrated elevations in post-exercise serum concentrations of IGF-1 were similar for both protocols, and did not occur until 1 hour post-exercise (13). Last, Fink et al. compared 14 young athletes (age: 18&#x2013;22 years) who had not participated in regular resistance training for at least 2 years, following short (30 sec) or long (2.5 min) rest between set durations during a routine of bench press and squats for 8 weeks, 2x/week, 4 sets/exercise, reps until failure/set, with 40% of 1RM, and a moderate rep tempo (2:0:1). The findings demonstrated similar increases in post-exercise serum concentrations of IGF-1 for both groups, following an initial session and the last session, despite longer rest between set durations resulting in a significant increase in exercise volume (11). These studies imply that&#xA0;post-exercise serum concentrations of IGF-1 are not influenced by rest between set duration, increases in exercise volume, resistance-training experience, and/or gender.

Two studies were located that investigated the relationship between protein synthesis and rest between set durations. McKendry et al. compared 16 males (Age: 24.5 &#xB1; 4.8 (18&#x2013;34) years) performing short (1 min) or long (5 min) rest between set durations during a routine of <a id="bilateral" data-tip="1552" target="_blank" href="/glossary-term/bilateral" class="glossary">bilateral</a> leg-press and knee-extensions, 4 sets/exercise, 75% of 1-RM, reps until failure/set, followed by ingestion of 25 g of whey protein. The findings demonstrated that 0-4 hours post-exercise myofibrillar protein synthesis was higher for the long rest between sets protocol; however, 24 - 48 hours post-exercise protein synthesis was similar for both protocols (16). Salvador et al. compared 8 resistance-trained participants (age: 23 &#xB1; 1 years) performing a routine of barbell back squats with 70% 1RM loads and two volume-equated protocols including a rest-redistribution protocol of 4 sets/exercise, 2 x 5 reps/set, short (30 sec) rest between reps 5 and 6, and moderate (1.5 min) rest between sets, or a conventional protocol of 4 sets, 10 reps/set, and moderate (2 min) rest between sets. The findings demonstrated that the rest-redistribution protocol resulted in higher average velocity, greater peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, and a slightly lower rate of perceived exertion during subsequent sets; however, anabolic signaling and protein synthesis were similar for both conditions based on blood and <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> biopsy samples collected at rest and 0, 2, and 5 hours post exercise (17). Although a pattern is not implied from these two studies alone, the findings are congruent with the studies on post-exercise serum concentrations of testosterone. That is, it is likely that the amount of protein synthesis is influenced more by exercise volume than rest between set duration, and any increases in protein synthesis noted following longer rests are actually the result of more reps/set.
<img title="Muscles when they are viewed under electromagnetic imaging" src="https://www.datocms-assets.com/25800/1649648760-muscle-fiber-types.jpg" alt="Staining of muscles under electromagnetic imaging">

<h3>Work-matched</h3>
Several studies have compared plasma lactate concentrations following protocols with similar workloads and varied rest between set durations. Millender et al. compared 14 healthy resistance-trained females (age: 22.9 &#xB1; 5.4 years) performing short (1 min) and long (3 min) rest between set durations during chest press and leg press, 4 sets/exercise, 75% of 1-RM loads, reps to failure/set, and a moderate tempo (2:0:1). The findings demonstrated that volume was higher for the long rest between set protocol, fatigue index was higher for the short rest between set protocol, and post-exercise serum concentrations of lactate were similar for both protocols (18). Machado et al. compared 10 healthy men (age: 25.6 &#xB1; 2.2 years) performing short (1 min), moderate (1.5 and 2 min), and long (3 min) rest between sets during a resistance training routine (chest press, pullovers, biceps curls, triceps extensions, leg extensions, and <a id="prone" data-tip="1561" target="_blank" href="/glossary-term/prone" class="glossary">prone</a> leg curls), for 4 sets/exercise, 10 reps/set, with 10-RM loads, and a fast tempo (1:0:1). The findings demonstrated that serum concentrations of lactate were significantly elevated 24-72 hours following exercise, and were similar for all groups (19). Lopes et al. compared 10 healthy young men (age: 23 &#xB1; 6.5 years) performing either short (30 sec and 1 min) or moderate (2 min) rest between set durations during a resistance training routine of 6 exercises (bench press, seated low row, shoulder press, back squats, leg press, and seated calf raises), for 4 sets/exercise, with 10 RM/set, and a moderate tempo (2:0:2). The findings demonstrated that longer rest between set durations resulted in an increase in load; however, post-exercise blood lactate concentrations were similar for all groups (20). Mohammadi et al. compared 40 untrained subjects (age: 25.4 &#xB1; 0.068) divided into 4 groups performing eccentric exercise with 85% of 1-RM for 50 total repetitions and a slow tempo (3:0:2), including short (1 min) rest between sets for 5 sets and 10 reps/set, short (1 min) rest between sets for 10 sets and 5 reps/set, long (3 min) rest between sets for 5 sets and 10 reps/set, and long (3 min) rest between sets for 10 sets and 5 reps/set. The findings demonstrated that immediately and 24-hours following exercise, all protocols resulted in similar increases in serum concentrations of lactate dehydrogenase (an enzyme that increases with lactate production) (21, 22). Martorelli et al. compared 12 resistance-trained men (age: 22.7 &#xB1; 3.2 years) performing short (1 min), moderate (2 min), or long (3 min) rest between sets during a routine of squats for 6 sets, 6 reps/set, with 60% of 1-RM, and a maximal voluntary concentric tempo (maxV) (2:0:maxV). Shorter rest between sets resulted in a larger loss in average <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> output during sets 2-6; however, the difference between 2 min (mean -4.3%) and 3 min (mean -2.6%) rest between sets was relatively small when compared to 1 min rest between sets, and post-exercise blood lactate concentrations were similar for all groups (23). These studies suggest that when total work/routine is similar, rest between sets has little, if any influence on post-exercise plasma concentrations of lactate. Further, these studies have demonstrated that findings apply to both men and women, experienced and inexperienced exercisers, and that there may be no correlation between lactate concentrations and loss in <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, number of reps per set, and/or rate of perceived exertion.
<h3>More Volume or Shorter Rest Between Sets with Repetitions Until Failure</h3>
Additional studies suggest that short rest between set durations and increases in volume may have a significant effect on lactate concentrations.&#xA0;As mentioned above, the series of studies by Kraemer et al. compared resistance-trained men and women, while performing short (1 min) or long (3 min) rest between set durations, and moderate load/high volume (10RM x 3 sets/exercise) or heavy load/low volume (5RM x 3 or 5 sets/exercise) protocols, demonstrating larger increases in serum lactate with shorter rest periods and more exercise volume (7-9, 14). Also mentioned above,&#xA0;Agostinete&#xA0;et al. compared 8 physically active men (23.5 &#xB1; 3.1) performing short (30 sec.) rest between sets, moderate&#xA0;(90 sec.) rest between sets, or a combination of the short rest between sets duration with the same number of reps performed with moderate rest (achieved by adding sets). The routine included squats, bench press and T-bar rows, for 4 sets/exercise (except the additional sets group), with 70% of 1-RM loads, reps until failure/set, and a moderate tempo (1:1:1). The findings demonstrated that the moderate (longer) rest between sets protocols resulted in a significant increase in reps/set and exercise volume, post-exercise serum concentrations of lactate were higher for the moderate rest group when compared to the short rest group; however, the highest concentrations of lactate were exhibited by the group performing short rests with moderate rest equated volume (3). Increases in volume, and/or the combination of reps until failure/set with shorter rest between set durations, will likely result in larger increases of post-exercise serum concentrations of lactate.&#xA0;Further, there is likely no difference in post-exercise lactate concentrations when comparing different rest between set durations that are longer than 2 minutes.
<h3>Especially Short Rest Between Set Durations</h3>
Additional research implies short rest between set durations may have an especially significant influence on post-exercise serum concentrations of lactate.&#xA0;Hiscock et al. compared 10&#xA0;recreationally resistance-trained men&#xA0;(age:&#xA0;26.8 &#xB1; 4.5 years)&#xA0;performing 4 different protocols of biceps curls with moderate (2 min) or long (4 min) rest between sets, 8 reps/set or reps to failure/set, for 3 sets with 70% 1-RM loads. The findings demonstrated no difference in serum concentrations of blood lactate when comparing 2 min and 4 min rest between set durations; however, higher concentrations of serum lactate were demonstrated following reps to failure/set when compared to 8 reps/set (24). Abdessemed et al. compared 10 males performing short (1 min), long (3 min), and very long (5 min) rest between sets during bench press for 10 sets, 6 reps/set, 70% of 1RM load, and a fast tempo (approx. 1 sec/rep). The findings of the study demonstrated that the 1 min rest between sets protocol resulted in significantly higher post-exercise plasma lactate concentrations, and a significant reduction in mean power/rep for reps 4-6, for sets 4 - 10. Further, lactate accumulation and mean <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> were similar for 3 min and 5 min rest between set protocols (25). Hernandez-Davo et al. compared 31 college students (18 males and 13 females, age: 21 - 34) performing short (1-min), moderate (2 min), and long (3-min) rest between sets, during bench press throws, for 5 sets, 8 reps/set, 40% of 1RM load, with explosive tempos. The findings demonstrated that 1 min rest between sets resulted in larger decreases in <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> for sets 2-5, larger increases in post-exercise plasma lactate concentration, and increased perceived rate of exertion. Additionally, 2 and 3 min rest resulted in similar decreases in <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> for sets 2-5, similar lactate concentration, and similar rates of perceived exertion (26).&#xA0;Senna et al. (2012) compared 12 resistance-trained men (age: 23.41 &#xB1; 2.53 years) performing short (1 min) or long (3 min) rest between sets, during either bench press or chest flyes, during 4 non-consecutive testing sessions, 5 sets/session, 10RM/set, with a self-paced slow and controlled tempo. Findings demonstrated that the number of reps performed during 2nd and 3rd sets was significantly higher with the 3 min rest between sets protocol, post-exercise plasma concentrations of lactate were significantly higher when performing chest flyes with the 1 min. rest between sets protocol, and lactate concentration were similar when performing bench press with either short or long rest between sets (27).&#xA0;In addition to the conclusions discussed above,&#xA0;short (&lt; 1 min) rest between set durations, may have an especially significant influence on post-exercise serum concentrations of lactate; further, the effects of short rest between set durations may be more pronounced when performing single joint exercises.&#xA0;

<h3>No Difference with Different Volumes</h3>
Studies have compared increases in post-exercise serum concentrations of creatine kinase following exercise with different rest between set durations and volumes. In two studies mentioned above,&#xA0;Rahimi et al. compared&#xA0;10 resistance-trained men (20.37 &#xB1; 2.24 years) performing either short (1 min) or moderate (1.5 min and 2 min) rest between set durations during a routine of squats and bench press, for 4 sets/exercise, 85% of 1-RM loads, reps to failure/set, with a moderate tempo (3:0:1).&#xA0;The findings demonstrated that post-exercise serum concentrations of creatine kinase were similarly elevated for all 3 groups (15).&#xA0;Ghaderi et al. compared 10 resistance-trained men (22 &#xB1; 2 years) performing short (1 min) or moderate (1.5 min and 2 min) rest between set durations, in counter-balanced order on non-consecutive days, during a routine of squats and bench press, 4 sets/exercise, 85% of 1-RM load, reps until failure/set, with a moderate tempo (3:0:1). The findings demonstrated that all protocols resulted in similar exercise volume, and similar increases in post-exercise serum concentrations of creatine kinase, creatine kinase myocardial band, and lactate dehydrogenase (28). Silva et al. compared 27 healthy sedentary men (age: 18&#x2013;20 years) performing either short (30 sec) or moderate (90 sec) rest between sets during biceps curls for 5 sets, 85% of 1-RM load, and reps until failure/set. The findings demonstrated that the moderate rest group performed significantly more work/reps; however, increases in post-exercise serum creatine kinase were similar for both groups (29). Evangelista et al. compared 28 healthy sedentary men (age: 18 &#xB1; 1 years) performing either short (1 min) or long (3 min) rest between sets during biceps curls for 3 sets, 40% of maximum voluntary isometric contraction (MVIC), reps until failure/set, and a slow tempo (2:1:2). The findings demonstrated that the long rest between sets group performed significantly more work/routine; however, increases of post-exercise serum concentrations of creatine kinase and post-exercise soreness were similar for both groups (30). Rodrigues et al. compared 20 untrained men (age: 18.65 &#xB1; 0.5 years) performing short (1 min) or long (3 min) rest between sets during an upper body routine (barbell bench press, machine lat pull-downs, seated machine shoulder press, machine triceps extensions, and free weight standing biceps curls) for 3 sets/exercise, 80% of 1-RM load, and reps until failure/set. The findings demonstrated that the long rest group performed significantly more reps/set and work; however, increases in post-exercise serum creatine kinase and lactate concentrations were similar for both groups (31). These studies demonstrate that post-exercise serum concentrations of creatine kinase are similar for both sedentary and experienced exercisers following protocols with varied rest between set durations, even when longer rest between set durations results in a significant increase in work/routine.
<h3>Work-matched</h3>
Several studies demonstrate that routines resulting in similar work, but with different rest between set durations, result in similar post-exercise serum concentrations of creatine kinase. As mentioned above, Machado et al. compared 10 healthy men (age: 25.6 &#xB1; 2.2 years) performing short (1 min), moderate (1.5 and 2 min), or long (3 min) rest between set durations during a resistance training routine (chest press, pullovers, biceps curls, triceps extensions, leg extensions, and <a id="prone" data-tip="1561" target="_blank" href="/glossary-term/prone" class="glossary">prone</a> leg curls), 4 sets/exercise, 10 reps/set, with 10 RM load, and a fast tempo (1:0:1). The findings demonstrated that serum creatine kinase and lactate were significantly elevated 24-72 hours following exercise, and were similar for all groups (19). Also mentioned above, Mohammadi et al. compared 40 untrained subjects (age: 25.4 &#xB1; 0.068) divided into 4 groups performing eccentric exercise with 85% of 1-RM for 50 total reps and a slow tempo (3:0:2), including short (1 min) rest between sets for 5 sets and 10 reps/set, short (1 min) rest between sets for 10 sets and 5 reps/set, long (3 min) rest between sets for 5 sets and 10 reps/set, and long (3 min) rest between sets for 10 sets and 5 reps/set. The findings demonstrated that all protocols resulted in similar increases in serum creatine kinase and lactate dehydrogenase concentrations immediately following and 24 hours after exercise (21, 22). Azizbeigi et al. compared 20 untrained men (age: 22.2 &#xB1; 2.2 years) performing either moderate (90 sec) or long (3 min) rest between sets during a resistance training routine (chest press, lat pull down, leg extension, leg curl, and back squat) for 4 sets/exercise, 6 RM/set, with long (5 min) rest between exercises. The findings demonstrated that both groups exhibited significant but similar increases in post-exercise serum concentrations of malondialdehyde (MDA) and creatine kinase (CK) (32). Last, Ribeiro et al. compared 14 resistance-trained males (age: 24.5 &#xB1; 5 years) performing short (1 min) and long (3 min) rest between sets during a resistance training routine (bench press, cable pulldowns, military press, biceps curls, triceps curls, leg press, leg extensions, and lying leg curl) with 3 sets/exercise, 10 RM load, 10 reps/set. Findings demonstrated that post-exercise serum creatine kinase was similarly elevated for both groups (33). These studies included protocols with similar work performed for each routine; better isolating rest between sets as the <a id="independent-variable" data-tip="1440" target="_blank" href="/glossary-term/independent-variable" class="glossary">independent variable</a>. Following varied rest between set durations, similar serum concentrations of creatine kinase were demonstrated. This implies that rest between sets does not have a significant influence on post-exercise serum concentrations of creatine kinase.
<h3>Work-matched and Short Rest Between Sets</h3>
Two studies contradict the findings above, demonstrating that when routines are work-matched, shorter rest between set durations may alter post-exercise serum concentrations of creatine kinase. Kraemer et al. (1993) compared 8 recreationally resistance-trained men (age: 24.7 &#xB1; 1.6 years) comparing short (1 min.) and long (3 min) rest between sets, and moderate (10RM x 3 sets/exercise) and heavy (5RM x 3 or 5 sets/exercise) loads, on 4 non-consecutive days, during a typical &quot;bodybuilding&quot; routine of 8 exercises (bench press, double leg extension, military press, bent leg incline sit-ups, seated rows, lat pull down, arm curls, leg press). The findings demonstrated that post-exercise plasma concentrations of creatine kinase were elevated following all protocols, were most significantly influenced by rest between sets, and were most elevated following the 1 min rest between sets/10RM protocol (34). Mayhew et al. compared 9 resistance-trained males (age: 22.2 &#xB1; 0.3 years) performing short (1 min) and long (3 min) rest between sets during a routine of leg press for 10 sets, 10 reps/set, with 65% of 1-RM. The findings demonstrated that post-exercise serum concentrations of creatine kinase were significantly higher following short rest between set durations (35). It may be worth noting that these studies used protocols including a much larger volume of exercise when compared to the studies mentioned above. Although caution is warranted when attempting to interpret the results from a relatively small group of conflicting studies, these studies may demonstrate higher post-exercise serum concentrations of creatine kinase with shorter rest between set durations, but only when comparing work-matched, high-volume routines (e.g. advanced bodybuilding style routines).

<h3>Immune System Markers</h3>
Several studies have reported the effect of various rest between set durations on post-exercise serum concentrations of lymphocytes. In a study mentioned above,&#xA0;Agostinete&#xA0;et al. compared 8 physically active men (23.5 &#xB1; 3.1) performing short (30 sec) or moderate&#xA0;(90 sec) rest between sets, or a combination of the short rest with the same number of reps performed with moderate rest (achieved by adding sets). The findings demonstrated that post-exercise serum concentrations of IL-6 were highest following the short&#xA0;(30 sec) rest between sets protocol, and IL-10 and&#xA0;IL-1ra were similar for all groups (3).&#xA0;Also mentioned above, Mayhew et al. compared 9 resistance-trained males (age: 22.2 &#xB1; 0.3 years) performing short (1 min) and long (3 min) rest between set durations during a routine of leg press for 10 sets, 10 reps/set, with 65% of 1-RM. The findings demonstrated post-exercise serum concentrations of leukocytes, lymphocytes, and monocytes were higher for the short rest between sets protocol, and elevation of neutrophils was similar for both protocols (35). Rossi et al. compared 8 resistance trained subjects (age = 24.6 6 4.1 years) performing short (30 sec) or moderate (1.5 min) rest between sets during squats and bench press for 4 sets, reps until failure/set, 70% of 1-RM load, and a moderate tempo (1:1:1). The findings demonstrated that significantly more reps and exercise volume was performed during the moderate rest between sets protocol, and only the moderate rest between sets protocol resulted in significant increases in post-exercise serum concentrations of inflammatory markers (IL-6 and IL-10) (36). An RCT by Kraemer et al. (1996) compared 9 recreationally weight-trained men (26.9 &#xB1;4.8 years) performing control (no exercise), short (1 min), and long (3 min) rest between sets protocols following a routine of leg press, for 8 sets, 10 reps/set, 75 - 90% of 1-RM. The findings demonstrated that both exercise protocols resulted in similar increases in post-exercise serum cortisol and leukocytes; however, there was no correlation between cortisol and leukocyte concentrations (37). These studies suggest that shorter rest between set durations increases post-exercise serum concentrations of monocytes, lymphocytes, and leukocytes (especially IL-6); however, it is likely this relationship is dependent on performing a sufficient volume of exercise. Further, some evidence suggests shorter rest between set durations may increase cortisol concentrations; however, it is unlikely that there is a correlation between leukocyte and cortisol levels.
<h3>Inflammatory Markers</h3>
Additional studies have investigated the relationship between rest between set durations and inflammatory markers. Mohammadi et al. compared 40 untrained subjects (age: 25.4 &#xB1; 0.7 years) divided into 4 groups, performing either short (1 min) or long (3 min) rest between sets during eccentric biceps curls performed for either 5 sets of 10 reps/set, or 10 sets of 5 reps/set, with 85% of 1-RM, and a 3 sec eccentric tempo. The findings demonstrated that all protocols resulted in significant and similar increase in post-exercise serum concentrations of tumor necrosis factor-&#x3B1; (TNF-&#x3B1;), a decrease in range of motion (ROM), and an increase in soreness and arm circumference (39). Etemad et al. compared 30 untrained subjects (age 19 - 28 years) performing moderate (1.5 min) or long (3 min) rest between set durations during a resistance training routine of 8 exercises (bench press, pull downs, curls with pulleys, biceps and triceps exercise with a barbell, squats using a hack squat machine, lat pull downs, and sit-ups) for 8 weeks, 3 sets/exercise, 8-12 reps/set, with 50% of 1-RM loads on week 1, progressed to 85% of 1-RM on week 8. The findings demonstrated a significant decrease in post-exercise serum concentrations of homocysteine and c-reactive protein over the course of the training period, and the reductions were significantly larger for the long rest between sets group (40). These studies demonstrate that exercise may result in a significant increase in post-exercise serum concentrations of inflammatory markers, including TNF-&#x3B1;, homocysteine, and c-reactive protein (along with swelling and a loss of ROM); however, it is likely that rest between set duration has little, if any influence on the magnitude of elevation. Additionally, elevation of inflammatory markers is likely to decrease as an adaptation to long-term training, and longer rest between set durations may enhance adaptation.

<h3>Cortisol and Testosterone/Cortisol Ratio</h3>
Several of the studies mentioned above have investigated the effects of rest between set durations on post-exercise serum concentrations of cortisol, testosterone, and cortisol/testosterone ratio. Mayhew et al. compared 9 resistance-trained males (age: 22.2 &#xB1; 0.3 years) performing short (1 min) and long (3 min) rest between sets during a routine of leg press for 10 sets, 10 reps/set, with 65% of 1-RM. The findings demonstrated that post-exercise serum concentrations of cortisol did not increase following either rest between set durations (35). An RCT by Kraemer et al. (1996) compared 9 recreationally weight-trained men (26.9 &#xB1; 4.8 years) performing a control (no exercise), short (1 min), and long (3 min) rest between set durations, following a routine of leg press, for 8 sets, 10 RM/set, 75 - 90% of 1-RM. The findings demonstrated that both rest between set durations resulted in similar increases in post-exercise serum concentrations of cortisol (37). Mohamad-Panahi et al. compared 17 male cadet wrestlers (16.7&#xB1;0.6 yr) performing moderate (1.5 min.) or long (4-min.) rest between set durations during bench press for 4 sets, with 60% of 1-RM, and repetitions performed until failure. Longer rest between sets resulted in a significant increase in reps/set and exercise volume, concentrations of testosterone only increased following the long rest between set protocol; however, both long and short rest between sets resulted in similar decreases in cortisol concentrations (1).&#xA0;Abbasi et al. compared 16 resistance-trained men performing either short (30 sec) or moderate (2 min) rest between set durations following 8 weeks of a lower body resistance training (hamstrings with machine, squats, deadlifts, and leg press) for 4 sets/exercise, with 8-10 RM/set. The findings demonstrated that post-exercise serum concentrations of testosterone and cortisol (and testosterone/cortisol ratio) were similar for both groups (4). Last, Ahtiainen et al. compared 13 recreationally resistance-trained men (28.7 &#xB1; 6.2 years) performing either moderate (2 min) or long (5 min) rest between sets during 3 months of training with work-matched routines. The findings demonstrated that both routines resulted in similar changes in post-exercise serum concentrations of testosterone (increase) and cortisol (decrease) (5).&#xA0;These studies suggest that rest between set durations likely has little influence on post-exercise serum concentrations of cortisol, and considering that cortisol may not change, increase, or decrease following exercise, it is more likely that alterations in testosterone/cortisol ratios are the result of more significant and <a id="reliability" data-tip="1795" target="_blank" href="/glossary-term/reliability" class="glossary">reliable</a> increases in testosterone.&#xA0;
<h3>Short Rest Between Set Durations Effect Cortisol Levels</h3>
A few studies mentioned above demonstrate differences in post-exercise serum concentrations of cortisol when short rest between set durations were performed. Rahimi et al. compared 10 experienced resistance-trained men (20.37 &#xB1; 2.24 years) performing either short (1 min) or moderate (1.5 min and 2 min) rest between sets during a routine of squats and bench press, for 4 sets/exercise, 85% of 1-RM loads, reps to failure/set, with a moderate tempo (3:0:1). The findings demonstrated that post-exercise serum concentrations of cortisol were significantly higher for the 1 min and 1.5 min protocols when compared to the 2 min rest between sets protocol (2, 15). A Kraemer et al. (1993) study mentioned above compared 8 recreationally resistance-trained men (age: 24.7 &#xB1; 1.6 years) comparing short (1 min.) and long (3 min) rest between sets, and moderate (10RM x 3 sets/exercise) and heavy (5RM x 3 or 5 sets/exercise) loads during a typical &quot;bodybuilding&quot; routine of 8 exercises (bench press, double leg extensions, military press, bent leg incline sit-ups, seated rows, lat pull downs, arm curls, leg press). The findings demonstrated that post-exercise plasma concentrations of cortisol were only significantly elevated for the shorter rest and higher volume protocol (1 min rest between sets and 10 RM/set) (14). Last, Buresh et al. compared 12 resistance-trained men (24.8 &#xB1; 5.9 years) performing either short (1 min) or moderate (2.5 min) rest between sets during a 2-day split-routine for 10 weeks, 4 sessions (2 days per split)/week, 2-3 sets/exercise, 10 reps/set, with a load that resulted in failure in less than 10 reps during the 3rd set. The findings demonstrated that initial post-exercise serum concentrations of testosterone and cortisol were significantly higher following the short rest between sets protocol; however, the differences diminished and were not statistically significant by the end of the 10 week training period (10). These studies suggest that a combination of short rest between sets (&lt; 90 sec) and an increase in exercise volume&#xA0;(e.g. multiple exercises, reps until failure, etc.) may result in higher post-exercise serum concentrations of cortisol; however, the higher concentrations are likely to diminish following several weeks of training.&#xA0;

Electormyographic Activity and Cardiovascular Changes

<h3>Rest Between Sets Duration Does Not Influence EMG Activity</h3>
Several studies suggest that rest between set duration does not have a significant effect on EMG activity. Jambassi et al. compared 21 resistance-trained older women (age: 66.4 &plusmn; 4.4 years) performing short (1 min) or long (3 min) rest between set durations during a resistance training routine (leg press, fly, triceps curls, lat pull-downs, biceps curls, shoulder press or shoulder shrug, calf raise, and abdominal exercises) for 8 weeks, 3 sets/exercise, 15 reps/set, with a fast tempo (1:0:1), and a load that resulted in reps to failure on the 3rd set. The findings demonstrated that longer rest between sets resulted in an insignificant trend toward larger loads lifted during training, and a larger increase in 15 RM strength; however, training volumes were similar and neither program resulted in changes in EMG activity during strength testing (40). Another study by Jambassi et al. (2020) compared 21 resistance-trained older women (age: 66.4 &plusmn; 4.4 years) performing short (1 min) or long (3 min) rest between set durations during a leg exercise, for 3 sets/session, 15 RM loads, and reps to failure/set. The findings demonstrated that the longer rest between set durations resulted in a significant decrease in the reduction in reps performed during additional sets, an increase in exercise volume, a larger decrease in post-exercise maximum voluntary isometric contraction (MVIC), and no significant changes in vastus lateralis or vastus medialis EMG activity (41). Ibbott et al. compared 16 resistance-trained athletes performing long (3 min and 5 min) and self-selected (approximately 3.5 - 4.5 min) rest between set durations during heavy lower body resistance training, for 5 sets/session, and 5 reps/set. The findings demonstrated that all conditions resulted in similar decreases in velocity, similar decreases in EMG activity, and similar increases in perceived exertion (42). Guan et al. compared 10 male university basketball players (age: 20 &plusmn; 1 years) performing short (1 min), moderate (2 min), and long (3 and 5 min) rest between set durations during smith machine squat jumps for 3 sets, 10/reps set, with 30% of 1-RM load, and a tempo that included slow controlled eccentric contractions and explosive concentric contractions. The findings demonstrated similar changes in peak velocity, EMG activity, and muscle oxygenation for all rest between set durations (43). In summary, these studies suggest that rest between set duration does not have a significant effect on EMG activity, regardless of age, training experience, or type of training (moderate load, heavy load, high velocity).
<h3>Rest Between Sets Influences EMG Activity</h3>
Additional studies have demonstrated some changes in EMG activity following training with different rest between set durations. Azzeme et al. compared 15 resistance-trained men (age: 20-25 years) performing short (1 min) or moderate (1,5 min and 2 min) rest between sets during a routine of bent over rows and bicep curls (5 min rest between exercises), 3 sets/exercise, reps to failure/set, 75% of 1-RM loads, with a moderate (2:0:2) tempo. The findings demonstrated that longer rest between set durations resulted in more total reps and greater average muscle EMG activity (latissimus dorsi and biceps brachii) during sets 2 and 3 (44). Miranda et al. (2018) compared 15 recreationally trained women performing short (1 min) or long (3 min and 5 min) rest between sets during 45&deg; leg press, 4 sets/exercise, 10 reps/set, with 70% of 1-RM loads. The change in EMG amplitude for the time coefficient and spectral fatigue index (Cf5) indicated higher levels of fatigue for all muscles following the 3 min rest between sets protocol, when compared to the 1 min or 5 min protocols. Further, the rectus femoris and vastus lateralis exhibited signs of fatigue by set 3, whereas the vastus medialis and biceps femoris exhibited signs of fatigue by set 4 (45). Lockart et al. compared 12 healthy males performing short (1 min) and long (3 min) rest between set durations, in hypoxic (FIO2 = 15%) and normoxic (FIO2 = 21%) environments during leg extensions for 5 sets/session, 10 reps/set, 70% of 1-RM loads. The findings demonstrated that shorter rest periods resulted in larger increases in EMG activity and perceived exertion during additional sets. Further, both groups exhibited similar increases in post-exercise plasma lactate concentration and muscle soreness, and hypoxia did not significantly influence any outcome measure (46). Last, Hirono et al. compared 42 untrained young men (age: 22.9 &plusmn; 2.4 years) performing short (20 sec and 1 min) and long (3 min) rest between sets during knee extensions (resisted by ankle weights) for 12 sets/session, 10 reps/set, with 30% of 1-RM load, with a moderate (3 sec/rep) tempo. The findings demonstrated that the short rest between sets groups (20 sec and 1 min) exhibited a significant increase in muscle thickness (measured with ultrasound) following 3 sets, and the long rest between sets (3 min) demonstrated a significant increase in muscle thickness following 9 sets. Further, muscle EMG activity increased significantly during sets 4-6 and 7-9 for the short rest between set groups but did not increase for the long rest between sets groups (47). Unfortunately, each of these studies suggests EMG activity increases more for a different rest between set duration (shorter, middle, or longer duration). These studies also suggest that the relationship between EMG activity and rest between set duration is different for different muscles, is not affected by hypoxia, not influenced by muscle soreness, but is affected by muscle fatigue. Considering the studies above failed to demonstrate a statistically significant difference, and each of these studies implies a different relationship, it may be that EMG activity is not directly influenced by rest between set durations, but rest between set durations may have an indirect influence by affecting a variable that does have a direct effect (e.g. fatigue).

<h3>Blood Pressure</h3>
Several studies have investigated the effects of rest between set duration on blood pressure. Veloso et al. compared 16 normotensive resistance-trained men (age: 23 &#xB1; 3 years) performing short (1 min), moderate (2 min), or long (3 min) rest between sets, during a resistance training routine (inclined leg press, seated row, bench press, leg curls, triceps extensions, and barbell curls) for 3 sets/exercise, 8 reps/set, with set 1 at 80% of 1-RM, set 2 at 70% of 1-RM, and set 3 at 60% of 1-RM, and a moderate tempo (2:0:1-2). The findings demonstrated that the 3 rest between set durations resulted in similar reductions in diastolic blood pressure 15 - 30 minutes post-exercise (48). Figueiredo et al. compared 11 pre-hypertensive resistance-trained men (age: 26.1 &#xB1; 3.6 years) performing short (1 min) or moderate (2 min) rest between sets, during a resistance training routine (bench press, lat pull-downs, shoulder press, biceps curls, triceps extensions, leg press, leg extensions, and leg curls) for 3 sets/exercise, 8 - 10 reps/set, 70% of 1-RM, with a volitional tempo (no pause between concentric and eccentric phases). The findings demonstrated that both rest between set durations resulted in similar increases in systolic blood pressure during exercise and decreases in systolic and diastolic blood pressure post-exercise (49). Lemos et al. compared 15 resistance-trained men (age: 25 &#xB1; 4.5 years) performing short (30 sec) or moderate (90 sec) rest between sets during a resistance training routine (this order and reverse order: chest press, front lat pulldown, seated row, upright row, triceps curls, and biceps curls), for an unreported number of sets, 15 reps/set, 15 RM load, with a tempo that included no pause between eccentric and concentric contractions. The findings demonstrated a decrease in systolic and diastolic blood pressure for up to 60 minutes post-exercise, and the decrease was larger for the moderate rest between sets protocol (50). de Salles et al. compared 17 older normotensive resistance-trained men (age: 67.6 &#xB1; 2.2 years) performing short (1 min) or moderate (2 min) rest between sets during a resistance training routine (45&#xB0; leg press, bench press, leg extensions, wide grip lat pull down, leg curls, seated military press, and seated calf raises) for 3 sets/exercise, 10 reps/set, 70% of 1-RM load, with a tempo that included no pause between eccentric and concentric contractions. The findings demonstrated that both protocols reduced post-exercise systolic blood pressure for up to 60 minutes; however, short rest between sets (1 min) significantly reduced diastolic blood pressure 50 min post-exercise, and moderate rest between sets (2 min) significantly reduced diastolic blood pressure 60 min post-exercise. Additionally, the blood pressure response was greater at all time points for the moderate (2 min) rest between sets group (51). These studies suggest that rest between set duration is unlikely to have a significant effect on post-exercise systolic blood pressure; however, there is some evidence to suggest that longer rest between sets (and an increase in exercise volume) may result in a larger decrease in post-exercise diastolic blood pressure, and the decrease may take longer to reach significant levels.
<h3>Heart Rate and Heart Rate Variability</h3>
Studies have also investigated the effect of rest between set durations on heart rate and heart rate variability. Del Vecchio et al. compared 15 healthy (normotensive) untrained women (age: 22 &#xB1; 2 years) performing short (1 min) or long (3 min) rest between sets of leg extensions, for 5 sets/session, 10 reps/set, 70% of 1-RM loads. The findings demonstrated that the shorter (1 min) rest between set duration elevated systolic blood pressure, heart rate, and rate pressure product, during the last 10 sec of each set, and the last 30 sec of each rest between sets (52). Lima et al. compared 20 young normotensive, recreationally resistance-trained men (age: 23.9 &#xB1; 0.7 years) performing short (30 sec) or moderate (90 sec) rest between sets, during a resistance training routine (bench press, knee extensions, seated rows, knee curls, and front raise), for 3 sets/exercise, 10 reps/set, and 50% of 1-RM load. The findings demonstrated that the shorter rest between set duration had a larger effect on post-exercise heart rate (for up to 60 minutes), only the shorter rest between set duration had a significant effect on post-exercise heart rate variability, and neither rest between set duration changed post-exercise blood pressure (53). In the study mentioned above by Lemos et al., 15 resistance-trained men (age: 25 &#xB1; 4.5 years) were compared performing short (30 sec) or moderate (90 sec) rest between sets during a resistance training routine, demonstrating that both protocols resulted in similar alterations in heart rate variability for up to 60 minutes post-exercise (50). These studies suggest that when compared to moderate or long, short rest between set durations (&lt; 90 sec) have a larger effect on heart rate and systolic blood pressure during exercise, and heart rate and heart rate variability for up to 60 minutes post-exercise.
<img src="https://www.datocms-assets.com/25800/1653665380-systolevs_diastole.png" title="Blood Pressure - Systole vs Diastole. Author: BruceBlaus. Wikipedia." alt="Image of the heart during systolic and diastolic blood pressure">
<h3>Respiration, Oxygen Consumption, and Energy Expenditure</h3>
The effect of rest between set durations on respiration, oxygen consumption, and energy expenditure has also been investigated. Guan et al. compared 10 male university basketball players (age: 20 &#xB1; 1 years) performing short (1 min), moderate (2 min), and long (3 and 5 min) rest between set durations during smith machine squat jumps for 3 sets, 10/reps set, with 30% of 1-RM load, and a tempo that included a slow controlled eccentric contraction and explosive concentric contraction. The findings demonstrated that each of the rest between set durations resulted in similar changes in peak velocity, EMG activity, and <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> oxygenation during sets 2 and 3 (43). Farinatti et al. compared 10 healthy resistance-trained men (age: 26 &#xB1; 3 years) performing short (1-min) and long (3 min) rest between sets during horizontal leg press or chest flyes, for 5 sets/exercise, 10 reps/set, 15 RM load, with a fast tempo (1:0:1). The findings demonstrated that net oxygen uptake, excess post-exercise oxygen consumption (EPOC), and energy expenditure were similar for both short and long duration rest between sets; however, the values were nearly double for leg press when compared to chest flyes (54). Castinheiras-Neto et al. compared 20 healthy subjects (26 &#xB1; 5 years of age) performing 1:3 and 1:5 work:rest ratios, in combination with 6 RM/set or 12 RM/set, during 3 sets of leg press. The findings demonstrated that heart rate was affected by workload and sets but not rest intervals; however, systolic blood pressure and rate pressure product increased more during protocols with the shortest rest intervals. Systolic blood pressure and rate pressure product were the highest during a 1:3 ratio and 6RM/set (shortest rest interval of any protocol) despite less volume (55). Ratamess et al. compared 8 resistance-trained men (age: 21.4 &#xB1; 2.4 years) performing short (30 sec. and 1-min), moderate (2 min), or long (3 min) rest between set durations during bench press, for 5 sets, 10 reps/set with 75% of 1-RM, or 5 reps/set with 85% of 1-RM. The findings demonstrated that the number of reps/set significantly decreased with shorter rest between set durations, the magnitude of this effect was larger for the 10 rep/set protocols, and oxygen consumption was significantly elevated during the first minute of recovery during all protocols. Ventilatory exchange and respiratory exchange ratios were elevated following the first set with a compounding effect during the second set for all protocols; however, the elevation only continued to compound for all sets when the rest between set duration was short (30 sec and 1 min). Additionally, post-exercise VO2 was similarly elevated (EPOC) following all rest between set durations (56). These studies suggest that although there may be a compounding increase in ventilatory exchange and respiratory exchange ratio with short rest between set durations (&lt; 1 min), VO2 max, oxygen uptake, excess post-exercise oxygen consumption, and energy expenditure are likely similar following exercise, regardless of the duration of rest between sets.

Hypertrophy, Strength and Power

<h3>Longer Rest Between Set Durations</h3>
Several studies have compared the effect of rest between set durations on hypertrophy and an increase in <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> cross-sectional area (CSA). Schoenfeld et al. compared 23 resistance-trained men (age: 18 - 35 years) performing short (1 min) or long (3 min) rest between set durations during a resistance training routine (barbell back squats, plate-loaded leg press, plate-loaded leg extensions, flat barbell press, seated barbell military press, wide-grip plate-loaded <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> pulldowns, and plate-loaded seated cable rows) for 8 weeks, 3x/week, reps until failure/set, 8-12 RM load, with a moderate tempo (2:0:1). The findings demonstrated that longer rest between set durations resulted in a trend toward increased total volume of exercise and significantly larger increases in strength and hypertrophy (57). Caha, J. compared 23 elite natural bodybuilders (age: 18&#x2013;30 years) performing short (30 sec or 1 min) or moderate (2 min) rest between set durations during an otherwise identical 5-day split program for 5 weeks. The findings demonstrated that longer rest between set durations resulted in more reps/set, an increase in exercise volume, a larger decrease in body fat, a larger increase in fat-free mass, and more hypertrophy. The largest differences were noted between the 30 sec and 1 min durations (58). These studies suggest that longer rest between sets may result in a significant increase in exercise volume, fat-free mass, and <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> hypertrophy. Additionally, the largest differences may be noted when increasing from short to moderate rest, although longer rest between sets (&gt; 3 min) is likely <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a>.
<h3>Work-matched Routines</h3>
Additional studies compare hypertrophy following routines with similar total work but different rest between set durations. In a study mentioned above,&#xA0;Ahtiainen et al. compared 13 recreationally strength-trained men (28.7 &#xB1; 6.2 years) with a cross-over study of two work-matched routines, each routine was performed for 3 months, and the order of the two routines was assigned randomly. The findings demonstrated that both routines resulted in similar changes in strength and&#xA0;quadriceps cross-sectional area (CSA) (5). Longo et al. compared 28 subjects (8 men, 10 women, age:&#xA0;22.5 &#xB1; 5.7 years) performing short (1 min) and long (3 min) rest between set durations, with either reps until failure/set or reps equal to the short rest between sets protocol (4 protocols), during a routine of <a id="unilateral" data-tip="1551" target="_blank" href="/glossary-term/unilateral" class="glossary">unilateral</a> leg press for 10 weeks, 2x/week, with 80% of 1-RM loads. The findings demonstrated that increases in strength were similar for all protocols; however, longer rest intervals and the ability to perform higher loads resulted in significantly larger increases in quadriceps cross-sectional area (59).&#xA0;These studies suggest that rest between set duration does not have an effect on hypertrophy when routines are work-matched; however, larger increases in hypertrophy may be exhibited when longer rest between sets results in more reps, larger loads, or an increase in total exercise volume.
<img src="https://www.datocms-assets.com/25800/1647453145-quadriceps-anatomy.jpeg" title="The vastus lateralis, vastus medialis, and rectus femoris muscles on the femur" alt="The quadricep muscles ">
<h3>Rest Between Sets, Anabolic Hormones, and Hypertrophy</h3>
Two studies mentioned above investigated the effects of rest between set durations on both hypertrophy and post-exercise serum concentrations of anabolic <a id="hormone" data-tip="1268" target="_blank" href="/glossary-term/hormone" class="glossary">hormones</a>.&#xA0;Fink et al. compared 14 young athletes (age: 18&#x2013;22 years) who had not participated in regular resistance training for at least 2 years, performing short (30 sec) or long (2.5 min) rest between set durations. The routine included bench press and squats for 8 weeks, 2x/week, 4 sets/exercise, reps until failure/set, with 40% of 1RM, and a moderate rep tempo (2:0:1). Significant and similar increases in growth <a id="hormone" data-tip="1266" target="_blank" href="/glossary-term/hormone" class="glossary">hormone</a> were noted after a single session, despite longer rest periods resulting in significantly more reps performed during sets 2-4. Longer rest periods also resulted in a trend toward more hypertrophy; however, statistical significance was not reached (11).&#xA0;Buresh et al. compared 12 resistance-trained men (24.8 &#xB1; 5.9 years) performing either short (1 min) or long (2.5 min) rest between sets during a 2 day split-routine for 10 weeks, 4 sessions (2 days per split)/week, 2-3 sets/exercise, 10 reps/set, with a load that resulted in failure in less than 10 reps during the 3rd set. The findings demonstrated that initial post-exercise serum concentrations of testosterone and cortisol were significantly higher following the short rest between sets protocol; however, the differences diminished and were not statistically significant by the end of the 10-week training period. Additionally, thigh CSA increased similarly for both groups, but arm cross-sectional area (CSA) increased more following the longer rest period protocol (10).&#xA0;These studies imply that shorter rest between set durations may result in larger increases in post-exercise serum concentrations of anabolic hormones; however, it is likely that these higher concentrations will dissipate with adaptations to training (within 10 weeks). Conversely, longer rest between sets may result in a significant increase in reps/set, exercise volume and <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> CSA; implying there is no correlation between hypertrophy and short-term increases in serum concentrations of anabolic <a id="hormone" data-tip="1268" target="_blank" href="/glossary-term/hormone" class="glossary">hormones</a>.&#xA0;

<h3>Longer Rest Between Sets Results in Larger Strength Gains</h3>
Several studies demonstrate larger improvements in strength following longer rest between set durations.&#xA0;Schoenfeld et al. compared 23 resistance-trained men (age: 18 - 35 years) performing short (1 min) or long (3 min) rest between set durations during a resistance training routine (barbell back squats, plate-loaded leg press, plate-loaded leg extensions, flat barbell press, seated barbell military press, wide-grip plate-loaded <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> pulldowns, and plate-loaded seated cable rows), for 8 weeks, 3x/week, reps until failure/set, 8-12 RM load, with a moderate tempo (2:0:1). The findings demonstrated that longer rest between sets resulted in a trend toward more total volume, and significantly larger increases in strength and hypertrophy (57). Jambassi et al. compared 21&#xA0;resistance-trained older women (age: 66.4 &#xB1; 4.4 years) performing short (1 min) or long (3 min) rest between set durations during a resistance training routine (leg press, chest flyes, triceps curls, lat pull-downs, biceps curls, shoulder presses or shoulder shrug, calf raises, and abdominal exercises) for 8 weeks, 3 sets/exercise, 15 reps/set, with a fast tempo (1:0:1), and a load that resulted in reps to failure on the 3rd set. The findings demonstrated that longer rest between sets resulted in a trend toward larger loads lifted during training, and a significantly larger increase in 15 RM strength at the end of the training period (40). These studies demonstrate that&#xA0;when compared to short (1 min), long (3 min) rest between set durations are likely to result in larger improvements in strength following resistance training (for at least 8 weeks).
Additional studies fail to reach statistical significance but demonstrate a similar trend toward longer rest between set durations resulting in larger improvements in strength. Fink et al. compared 14 young athletes (age: 18&#x2013;22 years) who had not participated in regular resistance training for at least 2 years, performing either short (30 sec) or long (2.5 min) rest between set durations. The routine included bench press and squats for 8 weeks, 2x/week, 4 sets/exercise, reps until failure/set, with 40% of 1RM, and a moderate rep tempo (2:0:1). Increases in strength and CSA were similar following 8 weeks of training with both rest periods; however, longer rest periods resulted in a trend toward larger improvements (11). Willardson et al. compared 15 former high school and college football players (age 20.71 &#xB1; 1.38 years) performing moderate (2 min) or long (4 min) rest between set durations during a 12-week periodized squat routine of heavy and light workouts (each performed 1x/week); heavy workouts included 70-90% 1-RM loads and reps until failure/set; light workouts included 60% of 1-RM loads and 8 reps/set. The findings demonstrated that increases in 1-RM squat strength were statistically similar for both groups; however, the longer rest between sets protocol result in a trend toward larger increases in strength (60). Mohamadimofrad et al. compared 40 male soccer players performing short (45 sec), moderate (1.5 min) or long (3 min) rest between set durations during a routine of bench press and squats for 8 weeks, 3x/week, 8 reps/set, 70% of 1-RM (weight increased 5% every 2 weeks), and 5 min rest between exercises. The findings demonstrated that all groups exhibited similar increases of 1-RM strength and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> during squats and bench press following training; however, again there was a small trend toward larger improvements for the long (3 min) rest between sets group (61). Although these studies failed to demonstrate statistically significant differences in strength improvements following longer rest between set durations, both studies demonstrate a trend that is congruent with the studies above. Further, it is possible that using deconditioned participants or daily undulated training were confounding variables.
<h3>No Difference</h3>
Novice/Deconditioned Exercisers
Some additional studies compare rest between set durations but fail to demonstrate any difference in strength improvements. Longo et al. compared 28 participants that were recreationally active but had not participated in resistance training for at least 6 months (8 men, 10 women, age:&#xA0;22.5 &#xB1; 5.7 years), performing short (1 min) and long (3 min) rest between set durations, with reps until failure/set, or an equal number of reps to the short rest between sets protocol (4 protocols), during a routine of <a id="unilateral" data-tip="1551" target="_blank" href="/glossary-term/unilateral" class="glossary">unilateral</a> leg press for 10 weeks, 2x/week, with 80% of 1-RM loads. The findings demonstrated that increases in strength were similar for all protocols; however, longer rest intervals and the ability to perform heavier loads resulted in significantly larger increases in quadriceps cross-sectional area (59).&#xA0;Gentil et al. compared 34 men without resistance training experience (age: 21.4 &#xB1; 3.2) performing short 1:3 work/rest ratios (~ 60 - 90 sec rest between sets) or long 1:6 work/rest ratios (~ 3 - 3.5 min rest between sets) during a whole body resistance training routine (2 upper body, 2 lower body, 1 mid-section exercise for each routine), for 12 weeks, 2x/week, 8-12 reps/set, 8-12 RM loads, reps until failure/set, with a moderate tempo (2:0:2). The findings demonstrated that both rest intervals resulted in similar increases in 1-RM bench press and leg press strength (62). These studies may imply that during the early phases of strength training (first 8-12 weeks), novice and deconditioned exercisers are likely to see similar increases in strength with short, moderate, or long rest between set durations.
Volume Equated
The effects of rest between set duration on strength improvements may be indirect and related to the effects of volume. As mentioned above,&#xA0;Ahtiainen et al. compared 13 recreationally resistance-trained men (28.7 &#xB1; 6.2 years) with a cross-over study of two work-matched routines; each routine was performed for 3 months and the order of the two routines was assigned randomly. The first routine was performed with moderate (2 min) rest between sets during 5 sets of leg press, 4 sets of squats, and leg extensions, with 10RM/set (lighter loads), and the second routine was performed with long (5 min) rest between sets during 4 sets of leg press, 3 sets of squats and leg extensions with 10RM/set (heavier loads). The findings demonstrated that both routines resulted in similar changes in strength and quadriceps cross-sectional area (CSA) (5). Simao et al. compared 12 resistance-trained men (age: 26.4&#xB1;5.1 years) performing short (1 min) or long (3 min) rest between set durations during a resistance training routine (bench press, leg-press 45&#xBA;, biceps curls, hack squat machine, front pull-ups, partial abdominal push-up, and tricep extensions) for 8 weeks, 3x/week, 3 sets/exercise, 10 RM load, and 8-10 reps/set (15-20 reps per set for abdominal exercises). The findings demonstrated that both groups exhibited similar improvements of 10 RM strength for all exercises (63). Rostameyan et al. compared 20 physically active male college students performing moderate (1.5 min) and long (2.5 min and 4 min) rest between set durations during a resistance training routine (bench press, biceps curls, front shoulder raises, ESCO, leg press, and back leg press) for 8 weeks, 3x/week, 4 sets/exercise, 10 reps/set, and 70% of 1-RM load (increased 5% every 2 weeks). Note, it is the author&apos;s guess that the leg exercises were poorly translated from the original published language and are actually leg press, leg extensions, and leg curls. The findings demonstrated that all groups exhibited similar improvements for endurance, maximum strength, and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> (64). Villanueva et al. compared 22 older, recreationally active men (age: 65.6 &#xB1; 3.4 years) performing short (1 min) and long (4 min) rest between sets, during 24 of 36 sessions of a periodized resistance training program performed over 12 weeks. Mesocycle 1 was performed for 4 weeks, 3x/week, 4-6 exercises/session, 2-4 sets/exercise, 8-15 reps/set, 8-15 RM load, with no rest between set durations listed, followed by mesocycle 2, dividing the groups into short (1 min) and long (4 min) rest between sets groups for 8 weeks, 3x/week, 4-6 exercises, 2-3 sets/exercise, 4-6 reps/set, with a 4-6 RM load. (Note, the volume was matched for both groups). The findings demonstrated that although both groups experienced significant improvements in lean body mass, body fat percentage, strength, functional outcomes and <a id="balance" data-tip="1190" target="_blank" href="/glossary-term/balance" class="glossary">balance</a>, the shorter rest interval group exhibited larger improvements in lean body mass, strength, and a trend toward larger improvements in functional outcomes (65). In summary, this research demonstrates that work/volume-matched routines result in similar improvements in strength. Based on this research, it may be reasonable to conclude that increases in performance, hypertrophy, strength, and endurance resulting from longer rest between set durations, are likely the result of longer rest between set durations resulting in more reps/set, and a significant increase in training volume/session. Further, the study by Villanueva et al. (65) suggests that if routines are work/volume-matched that shorter rest between set durations may result in larger increases in strength.
Insufficient&#xA0;Difference/Time
Two additional studies may have compared differences in rest between set durations that were not significant enough, and/or training periods that were not long enough to reach statistically significant results. Sim&#xE3;o et al. compared 33 resistance-trained men (age: 21.4 &#xB1; 2.5, range 20.2&#x2013;23.2) performing moderate (75 sec) or self-selected (average 90 -135 sec) rest between set durations during an upper body resistance training routine. The findings demonstrated that the self-selected rest period group performed more reps/set for every set after the second set; however, strength gains were similar at the end of 8 weeks (66). And, Piirainen et al. compared 24 novice male exercisers performing long (2 min) or heart rate (HR) mediated (average =&#xA0; 54 sec.) rest between set durations during 7 weeks of resistance training, 3x/week, 3 sets/exercise, 10 RM loads, with reps until failure/set. The study demonstrated that 1-RM and 10-RM strength increased similarly for both groups, despite the HR-mediated group performing shorter rest between sets (67). Both of these studies compared moderate rest between set durations, with approximately 1 min difference between groups, and a training period of less than 8 weeks. These may be insufficient differences in rest between set duration, or insufficient training period lengths, to identify statistically significant differences.

<h3>Effects on Strength and Force</h3>
Studies have demonstrated that rest between set durations may have a significant effect on maximum strength training (1 - 6 RM). Matuszak et al. (2012) compared 17 resistance-trained men (mean age 22.0 years) performing short (1 min) or long (3 min and 5 min) rest between set durations, between 2 attempts of 1-RM squats. The findings demonstrated that the number of participants who could successfully perform a second lift was 13/17 following short (1 min) rest, 16/17 following long (3 min) rest, and 15/17 following long (5 min) rest (68). Scudese et al. compared 16 trained men (age: 23.75 &#xB1; 4.21 years) performing short (1 min), moderate (2 min), and long (3 min and 5 min) rest between set durations, during bench press for 4 sets, 3-RM loads, reps to failure/set, and no attempt to control rep tempo. The findings demonstrated that short (1 min) rest between set durations resulted in significantly less reps in subsequent sets, starting with set 2, and moderate (2 min) and long (3 min and 5 min) rest between set durations resulted in a similar reduction in reps/set, starting with sets 3 and 4 (6). Gonzalez-Hernandez et al. compared 15 male university students performing short (1 min), or long (3 min and 5 min) rest between set durations during a routine of smith machine squats and bench press for 3 sets, 5 reps/set, 10 RM loads, with a tempo including a maximum concentric contraction. The findings demonstrated that when compared to long (3 min and 5 min), short (1 min) rest between set durations resulted in a decrease in peak force and peak velocity during the 2nd and 3rd sets. Reductions in peak force and velocity during additional sets were similar for long (3 min and 5 min) rest between sets durations (69). These studies suggest that short (&lt; 2 min) rest between set durations may have a significant influence on additional sets, including reductions of reps/set, exercise volume, peak force, and peak velocity; however, there may be little difference between moderate (2 min) and longer (&gt; 3 min) rest between set durations.
<h3>Effect on Kinematics</h3>
Additional studies demonstrate that rest between reps and sets may have a significant effect on kinematics and objective measures of force during Olympic lifts. Ammar et al. (2019) compared 9 elite-weightlifters (age: 24.4 &#xB1; 3.6 years) performing moderate (2 min) and long (3 min) rest between set durations during 2 successive 1-RM attempts of a jerk. The findings demonstrated that attempts following a long (3 min) rest between set duration resulted in enhanced maintenance of <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> jerk technique, as evidenced by a decrease in the 2nd attempt reduction of peak velocity, peak vertical bar displacement, peak knee, and hip extension during the drive phase, and a reduction of the increase in horizontal displacement (70). Another publication by Ammar et al. (2020) compared 9 elite weightlifters (age: 24.4 &#xB1; 3.6 years) performing moderate (2 min) or long (3 min) rest between set durations during 2 successive 1-RM attempts of a clean. The findings demonstrated that the additional minute of rest significantly reduced the decline in performance during the 2nd attempt. Objective measures demonstrated average reductions of loss of peak vertical displacement by 1.86%, backward motion during the first pull by 1.74%,&#xA0; forward motion during the second pull by 3.89%, and backward motion during the catch phase by 4.7%. Further, the loss of peak velocity was reduced by 2.22%, the loss of peak vertical <a id="ground-reaction-force" data-tip="1395" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction force</a> was reduced by 1.70%, and the loss of peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> was reduced by 2.14% (71). Tan et al. compared 15 male athletes (age: 21 &#xB1; 1.41 years) performing 10 sec, 30 sec or 50 sec rest between reps of barbell snatches for 3 sets, 5 reps/set, 85% of 1-RM loads, rep tempos as quick as possible (V:0:maxV), with long (5 min) rest between set durations. The findings demonstrated that during the pull phase the 50 sec rest between reps resulted in the fastest angular velocity for the hips; however, the 30 sec rest between reps resulted in the fastest angular velocity at the knee (there was no difference in angular velocities of the ankle). In the transition phase, the 30 sec rest between reps resulted in the fastest angular velocities at the hip, knee, and ankle, and the 10 and 50 sec rest between reps resulted in slower angular velocities. During the second pull, the 30 and 50 sec rest between reps resulted in the fastest angular velocities at the hip joint, and angular velocities following all rest between reps duration were similar for the knee and ankle. These findings imply that <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> rest between reps of heavy Olympic lifts is approximately 30 sec, unless angular velocity of the hip is the primary goal of a training session implying longer rest (50 sec) may be appropriate (72). These studies suggest that <a id="posture" data-tip="1660" target="_blank" href="/glossary-term/posture" class="glossary">form</a>, force, and the <a id="reliability" data-tip="1515" target="_blank" href="/glossary-term/reliability" class="glossary">reliability</a> of completing additional reps of near-maximal Olympic lifts improves following long (3 min) rest between set durations, and potentially longer rest between reps (30 - 50 sec).
<img title="Example of an Olympic Lift" src="https://www.datocms-assets.com/25800/1649512190-olympic-lift.jpg" alt="Olympic lifter performing the overhead snatch">

<h3>More Sets, More Rest:</h3>
Various studies have investigated the effects of rest between set duration on <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> (high-velocity) training.&#xA0;Hernandez-Davo et al. compared 31 college students (18 males and 13 females, age: 21 - 34) performing short (1 min), moderate (2 min), and long (3-min) rest between sets, during bench press throws for 5 sets, 8 reps/set, 40% of 1-RM load, and explosive tempos. The findings demonstrated that 1 min rest between sets resulted in larger decreases in <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> for sets 2-5, larger increases in post-exercise plasma lactate concentrations, and an increase in the rate of perceived exertion. Additionally, 2 and 3 min rest resulted in similar decreases in <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> for sets 2-5, similar lactate concentration, and similar rates of perceived exertion (26). Davo et al. compared 38 resistance-trained participants (18 men and 20 women, age: 18+ years) divided into stronger and weaker groups based on peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> output, while performing short (1 min), moderate (2 min), and long (3 min) rest between sets during bench press throws, for 5 sets/session, 8 reps/set, 40% of 1-RM load. The findings demonstrated that all groups exhibited a significant decrease in <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> during additional sets starting with set 2 following 1 min rest between set durations, stronger individuals could maintain <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> with moderate (2 min) rest, and weaker individuals needed long (3 min) rest to maintain <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>. Further, post-exercise serum lactate and delayed onset <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> soreness (DOMS) was higher for weaker groups and longer rest periods; however, rate of perceived exertion was higher with shorter rest periods (73). Garc&#xED;a-Ramos et al. compared 34 physically-active male college students (age: 22-33 years) performing continuous, 6 sec, or 12 sec rest between reps, during smith machine explosive bench press throws with 30%, 40% and 50% of 1-RM loads. Compared to continuous and 6 sec rest between rep durations, the reduction in bar velocity noted during the second half of the set was significantly reduced with the 12 sec rest protocol. Additionally, reductions in bar velocity may be dependent on the number of reps and load, as the continuous and 6 sec. rest protocols resulted in similar bar velocities until the 7th rep with 30 and 40% of 1-RM loads, and similar velocities until the 5th rep at 50% of 1-RM loads (74). These studies suggest long (3 min) rest between set durations improves the maintenance of velocity and reps/set during additional sets; starting with set 2 for weaker individuals, and set 3 for stronger individuals. Further, rest between reps (middle of set) may also be beneficial for maintaining maximal velocity.
<h3>Lower Body Power Training</h3>
Additional studies have investigated the effect of rest between set duration on lower body <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> (high-velocity) training. Ramirez-Campillo et al. compared 44 young soccer athletes without previous <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> experience (age 10.4 &#xB1; 2.3 years) divided into a control group, or 1 of 3 groups performing <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises (2 sets of 10 drop jumps from 20, 40, and 60 cm boxes) with short (30 sec and 1 min) or moderate (2 min) rest between sets for 7 weeks, 2 sessions/week, and 60 drop jumps/session. Note, this routine replaced some soccer drills, and the control group continued to perform those soccer drills. The findings demonstrated that all <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> groups exhibited similar improvements in jump height, change of direction, and kicking performance when compared to controls (75). Woolf et al. compared 16 (8 male, 8 female) participants (21.2&#xB1;0.9 yrs) performing short (30 sec or 60 sec) and moderate (90 sec) rest between sets of box jumps for 3 sets, 10 reps/set. The findings demonstrated that different rest periods did not result in significant differences in peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, velocity, average jump height or rate of perceived exertion (76). Baron et al. compared 24 professional ice hockey players (age: 22.65 &#xB1; 4.77, range 17 - 34 years) performing moderate (2 min) or long (3 min) rest between set durations of 3 &#xD7; 80 m sprint skating for 6 sets/session. The findings demonstrated that the average speed for all sets after set 1 and post-exercise serum lactate concentrations were higher with 3 min rest between set durations, average heart rate and perceived exertion was higher with 2 min rest between set durations, and peak heart rate was similar for both protocols (77). Wongsason et al. compared 30 competitive male rugby players (age: 20.00 &#xB1; 0.61 years) performing long (4 min) rest between sets, or long (4 min) rest between sets with 15 sec rest between every 5th reps, during jump squats, for 6 weeks, 3 sets/session, 30 reps/set, and 20% of 1-RM load. The findings demonstrated that the the rest between every 5th rep group exhibited significantly larger improvements in rate of force development, peak force, peak velocity and peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> (78). Last, Guan et al. compared 10 male university basketball players (age: 20 &#xB1; 1 years) performing short (1 min), moderate (2 min), and long (3 and 5 min) rest between set durations during smith machine squat jumps for 3 sets, 10/reps set, with 30% of 1-RM loads, and a tempo that included a slow controlled eccentric contraction and explosive concentric contraction. The findings demonstrated that all protocols resulted in similar peak velocity, EMG activity and <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> oxygenation during sets 2 and 3 (43). These studies likely imply that there is little difference in velocity or reps/set for lower body <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> (high-velocity) training when comparing short (1 min) and moderate (2 min) rest between set durations; however, significant increases in peak force, velocity, and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> may be achieved during additional sets with long (3 min) rest between set durations, and potentially rest between reps (middle of set). Note, based on research covered in &quot;<a href="https://brookbushinstitute.com/courses/introduction-power-training-high-velocity-training" target="_blank" rel="noopener">Power (High-Velocity) Training</a>&quot; and &quot;<a href="https://brookbushinstitute.com/courses/acute-variables-repetition-tempo" target="_blank" rel="noopener">Acute Variables: Repetition Tempo</a>&quot;, it is the author&apos;s opinion that Guan et al. (43) failed to see any difference in peak velocity due to a lack of a quick-eccentric, pre-stretch, or a stretch-shortening cycle; that is, the rep tempo recommended is not ideal for producing <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> or increasing velocity.
<h3>Increase in Strength, but Not Power</h3>
Several studies were located comparing rest between set durations, demonstrating that longer rest between sets increased strength, but not <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>. Pincivero et al. compared 15 healthy college-aged participants who had not participated in resistance training for at least 6 months (8 men, 7 women, age: 21.7&#xB1;1.9 years), performing either short (40 sec) or long (3 min) rest between set durations, during isokinetic knee extension/flexion for 4 weeks, 3x/week, 4 sets/session (increasing by 1 set each week), 10 reps/set of reciprocal concentric contractions, 10-RM load, with a tempo of 90&#xB0;/sec. The findings demonstrated that longer rest between sets resulted in larger increases in hamstring and quadriceps strength; however, both groups improved similarly on the single-leg hop <a id="assessment" data-tip="1482" target="_blank" href="/glossary-term/assessment" class="glossary">test</a> (79). Robinson et al. compared 33 resistance trained men (M age 20.4&#xB1;3.5 yrs) performing short (30 sec), moderate (90 sec), or long (3 min) rest between set durations during a split routine (Program A: *squats, *push press, bench press, straight leg deadlifts, and crunches; Program B: *clean pulls from mid-thigh, *power snatch, shoulder shrugs, bent-over rows, crunches) for 5 weeks, 4x/week (each routine 2x/week), 5 sets of 10 reps/session for &quot;*&quot; exercises, 3 sets of 10 reps/session for accessory (other) exercises, reps until failure/set, and 10-RM loads. Findings demonstrated that longer rest between sets resulted in heavier loads (relative to 1-RM), increased volume of exercise, and significantly larger increases in 1-RM squat strength; however, box jump performance improved similarly for all rest between set durations (80). Hill et al. compared 18 active females performing short (20 sec) or moderate (80 sec) rest between set durations during a progressive endurance training routine (parallel squats, bench step-ups with dumbbells, seated leg press, dumbbell lunges, knee extensions, leg curls, bench press, seated rows, lat pull downs, dumbbell shoulder press and abdominal crunches) for 5 weeks, 3x/week, 2-5 sets/exercise, and 15-20 RM load. The findings demonstrated that body mass did not significantly change for either group, the moderate (80 sec) rest between sets group performed a larger volume of exercise and exhibited larger increases in 3-RM leg press strength, and the short (20 sec) rest between sets group exhibited larger increases in post-exercise serum lactate concentrations and higher average <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> during repeated sprint tests (81). These studies demonstrate that longer rest between sets of strength exercise may result in significant increases in loads lifted during training, reps/set, exercise volume, endurance, and 1-RM strength; however, longer rest between strength exercises will not improve <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>. Research discussed in &quot;Acute Variables: Repetition Tempo&quot; demonstrates that no increase in <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> should have been expected from these routines which lack any high-velocity exercise. Even the increase in sprint performance demonstrated in the Hill et al. (81) study, is actually an increase in endurance; that is, the ability to maintain <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> with repeated sprints.

Volume

<h3>Resistance-trained Individuals</h3>
Several studies have demonstrated a significant increase in exercise volume when comparing long (3 min) to short (1 min) rest between set durations. Faraji et al. compared 13 resistance-trained men (age: 21.74 &#xB1; 2.25 years) performing short (1 min) or long (3 min) rest between set durations during a routine of 4 lower body exercises (leg press, leg extensions, leg curls, and parallel squats), 3 sets/exercise, 80% of 1-RM loads, reps until failure/set, and no attempt to control rep tempo. The results demonstrated that long (3 min) rest between sets resulted in significantly more reps/exercise and total exercise volume (82).&#xA0;Machado et al. compared 32 resistance-trained men (age: 226.4&#xA0;&#xB1; 3.2 years) performing short (1 min) or long (3 min) rest between sets during a resistance training routine (chest press, cable pull downs, biceps curls, triceps extensions, leg extensions, and <a id="prone" data-tip="1561" target="_blank" href="/glossary-term/prone" class="glossary">prone</a> leg curls), 3 sets/exercise, 10 reps/set, with 10-RM loads, and a moderate tempo (2:0:1). The long (3 min) rest between set duration resulted in a significant increase in exercise volume (83).&#xA0;Miranda et al. (2009) compared 12 resistance-trained men (age: 23.58 &#xB1; 2.53 years) performing short (1 min) or long (3 min) rest between set durations during a routine of 5 upper body exercises (barbell bench press, incline barbell bench press, pec deck fly, barbell lying triceps extension, and triceps pushdowns), for 3 sets/exercise, 8-RM loads, reps until failure/set, with a &quot;smooth and controlled&quot; tempo and no pause between reps. Again, the findings demonstrated that&#xA0;long (3 min) rest between sets resulted in&#xA0;significantly more reps/exercise and total exercise volume (84).&#xA0;Jambassi et al. (2013) compared 17 resistance-trained older women (age: 68.0 &#xB1; 5.9 years) performing short (1 min) or long (3 min) rest between set durations during horizontal leg press, for 3 sets, 15-RM loads, and reps until failure/set. The findings demonstrated that long (3 min) rest between sets, when compared to short (1 min) rest between sets, decreased the reduction in reps/set for the 2nd and 3rd set, and resulted in an increase in training volume (including time under <a id="tension" data-tip="1229" target="_blank" href="/glossary-term/tension" class="glossary">tension</a>) (85).&#xA0;Another study by, Jambassi et al. (2020) compared 21&#xA0;resistance-trained older women (age: 66.4 &#xB1; 4.4 years)&#xA0;performing short (1 min) or long (3 min) rest between sets during a leg exercise, 3 sets/exercise, 15-RM loads, reps until failure/set. The findings demonstrated that long (3 min) rest between sets resulted in a significant decrease in the reduction in repetitions performed in subsequent sets, and more total exercise volume (41). These studies demonstrate&#xA0;resistance-trained individuals may benefit from long (3 min) rest between sets due to the significant increase in reps/set and total exercise volume. This is primarily due to a reduction in the decrease in reps during additional sets that occurs with shorter rest between set durations.
<img title="Dr. Brent Brookbush demonstrating a dumbbell chest press" src="https://www.datocms-assets.com/25800/1649713391-dumbbell-chest-press.jpg" alt="A dumbbell chest press exercise">
<h3>Untrained Individuals</h3>
Additional studies suggest that long (3 min) rest between sets results in a significant increase in reps/set and exercise volume in trained and untrained individuals. In a study similar to Jambassi et al. (85) comparing 17 resistance-trained older women (mentioned above), Jambassi et al. compared 11 untrained older women (66.5 &#xB1; 5.0 years) performing short (1 min) or long (3 min) rest between set durations during horizontal leg press, for 3 sets, 15-RM loads, and reps until failure/set. The findings were similar, demonstrating that long (3 min) rest between set durations significantly decreased the reduction in reps/set for the 2nd and 3rd set, and resulted in a significant increase in exercise volume (including time under <a id="tension" data-tip="1229" target="_blank" href="/glossary-term/tension" class="glossary">tension</a>) (86). Saraiva et al. compared 12 untrained volunteers (9 women and 3 men,&#xA0; age: 20.7 &#xB1; 0.8 years) performing short (1 min) or long (3 min) rest between sets during a resistance training routine (chest press, leg press, front lat pulldowns, seated leg extensions, upright rows, seated leg curls, triceps extensions, calf raises, and biceps curls), for 2 sets/exercise, 10-RM load, reps until failure/set, moderate rep tempo (3 sec/rep), and the same rest interval between sets and exercises. The findings demonstrated that long (3 min) rest between sets increased reps performed during the second set, increased total exercise volume, and decreased the rate of perceived exertion (RPE) (87). These studies suggest that untrained individuals exhibit a similar response to longer rest between set durations as trained individuals, specifically a significant increase in the number of reps/set during sets following set 1, and an increase in the total volume of exercise.
<h3>Larger Range of Durations, Same Improvements</h3>
Studies have also demonstrated similar findings when comparing larger ranges of short (40 - 90 sec) and long (3 - 4 min) rest between set durations. Jambassi et al. (2010) compared 10 older women (age: 66.6 &#xB1; 5.8 years) performing moderate (1.5 min) or long (3 min) rest between set durations during Scott&apos;s bicep curls, for 3 sets/exercise, 10-12 RM loads, reps until failure/set, with a 3:0:2 tempo. The findings demonstrated that long (3 min) rest between sets significantly increased the ability to maintain reps/set for the 2nd and 3rd sets (88). Tibana et al. compared 10 recreationally trained men (age: 24.3 &#xB1; 3.5 years) performing moderate (1.5 min) or long (3 min) rest between set durations during Smith machine bench press, for 5 sets, 60% of 1-RM load, with a maximum voluntary concentric contraction (maxV) tempo. The findings demonstrated that long rest between sets resulted in an increase in reps/set, peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, and average <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> for sets 2 - 5 (89). An RCT by Garc&#xED;a-L&#xF3;pez et al. compared 21 untrained individuals (age: 25 &#xB1; 5 years) performing no exercise (controls), short (1 min) or long (4 min) rest between set durations of machine biceps curls for 5 weeks, 2x/week, 3 sets/exercise, 60% of 1-RM loads (increased 5% in weeks, 3, 4 and 5), reps until failure/set, and a tempo including a maximum velocity concentric contraction (maxV). The findings of the study demonstrated that the long rest between sets group was able to complete similar reps/set for sets 1 and 2, with a small decrease in reps during set 3, and the short rest between sets group exhibited a significant decrease in reps/set during sets 2 and 3 (90). Pincivero et al. compared 15 participants who had not participated in any resistance training for 6 months (8 men, 7 women, age: 21.7&#xB1;1.9 years) performing either short (40 sec) or long (3 min) rest between sets, during isokinetic knee extension/flexion for 4 sets/session, 10 reps/set of reciprocal concentric contractions, 10-RM loads, with a tempo of 90&#xB0;/sec. The findings demonstrated that peak <a id="torque" data-tip="1294" target="_blank" href="/glossary-term/torque" class="glossary">torque</a>, total work, and average <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> decreased significantly during sets 2-4 for the short (40 sec) rest between sets group, and the decrease was insignificant for the long (3 min) rest between sets group (91). These studies demonstrate that comparing a range of short and long rest between set durations (40 - 90 sec vs. 3 - 4 min) results in similar outcomes, including longer rest resulting in more reps/set for additional sets, an increase in exercise volume, and an increase of peak <a id="torque" data-tip="1294" target="_blank" href="/glossary-term/torque" class="glossary">torque</a>, average <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, and total work.
<h3>Rest Between Sets versus Exercise Order</h3>
Two studies demonstrate that exercise order may have a larger influence on reps/set when compared to rest between sets. Miranda et al. (2010) compared 16 recreationally trained men (age: 25 &#xB1; 4.16 years) performing short (1 min) or long (3 min) rest between set durations during a routine of 6 upper body exercises in the following order and reverse order (wide grip lat pull-downs, close grip pull-downs, machine seated rows, barbell row lying on a bench, dumbbell seated arm curls, and machine seated arm curls), 3 sets/exercise, 8-RM loads, reps until failure/set, and a smooth and controlled tempo with no pause between reps. The results indicate that long (3 min) rest between sets resulted in a significant increase in reps/exercise; however, exercise order had a larger influence on reps/set/exercise with more reps/set completed for exercises performed at the beginning of the routine (92). Cardozo et al. compared 16 young male football players (age: 19.8 &#xB1; 0.9 years) performing short (1 min), long (3 min), or self-paced rest between set durations during a routine performed in order and reverse order (bench press, back squats, biceps curls, and plantar flexion). The findings demonstrated that both the self-selected and long rest between set durations (similar average duration) resulted in more reps/set and an increase in exercise volume; further, more reps/set were performed for exercises at the beginning of the routine. The difference in reps/set/exercise was smaller between rest between set durations when compared to the difference in reps/set/exercise for exercises performed at the beginning or end of the routine (93). In summary, long rest between sets may increase reps/set and exercise volume; however, rest between set durations may be less influential on reps/set/exercise when compared to performing an exercise at the beginning or end of a routine.

<h3>Short Rest Between Sets</h3>
A few studies have compared short rest between set durations. Tibana et al. compared 15 male adolescents (age: 15.2 &#xB1; 1.2 years) and 15 adults (22.2 &#xB1; 2.7 years) without previous resistance training experience, performing short (30 sec and 1 min), and moderate (2 min) rest between set durations. The findings demonstrated that longer rest intervals resulted in more reps/set during 2nd and 3rd sets (30 sec &lt; 1 min &lt; 2 min), resulting in a significant increase in training volume. Further, the differences were larger between 1 min and 2 mins, than between 30 sec and 1 min rest between sets. Adolescents exhibited smaller differences in reps/set when comparing rest between set durations, suggesting a higher resistance to fatigue when compared to adults (94). Willardson et al. compared 15 resistance-trained men (age: 24.87 &#xB1; 4.07 years) performing short (30 sec and 1 min), and moderate (2 min) rest between set durations during squats and bench press, 5 sets/exercise, 15-RM loads, reps until failure/set, and a moderate (3:0:1) tempo. The findings demonstrated that for both the bench press and squats, moderate (2 min) rest between sets resulted in significantly more reps/set for all sets after the 1st set; however, the difference in reps/set did not reach statistical significance when comparing 30 sec and 1 min rest between set durations (95). Caruso et al. compared 30 physically active subjects (27 men and 3 women, age: 24.0 &#xB1; 0.8 years) performing short (30 sec and 1 min) rest between sets, or short (30 sec) rest between sets with &quot;vigorous repetitive kneading massage to prime movers&quot;, during a resistance training routine (45&#xBA; leg press, <a id="prone" data-tip="1561" target="_blank" href="/glossary-term/prone" class="glossary">prone</a> leg curls, seated shoulder press, and standing barbell curls) for 8 sets/exercise, reps until failure/set, with the following loads (% of 1-RM): 1st set 70%, 2nd and 3rd sets 80%, 4th and 5th sets 90%, 6th and 7th sets 75%, and 8th set 65%. The findings demonstrated that short (1 min) rest, when compared to short (30 sec) rest, resulted in significantly more reps/set, volume/exercise, and volume/session, and vigorous massage during rest between sets did not have a significant effect on reps/set or exercise volume (96). Paz et al. compared 15 resistance-trained men performing short (30 sec and 1 min), and moderate (1.5 min and 2 min) rest between set durations during a resistance training routine (bench press, lat pull downs, incline bench press, wide-grip seated rows, triceps extensions, and biceps curls). The findings demonstrated that shorter rest intervals resulted in a significant decrease in reps/set following the 1st set, and a decrease in training volume (97). Senna et al. compared 15 resistance-trained men (years: 26.40 &#xB1; 4.94 years) performing short (1 min), moderate (2 min), and long (3 min and 5 min) rest between set durations, during either bench press or machine chest fly, 5 sets/session, 3 RM loads, with reps until failure/set. The findings demonstrated that longer rest periods resulted in more reps/set and an increase in exercise volume; the largest difference between consecutive time intervals was between 1 min and 2 min rest periods, and the smallest difference was between 2 min and 3 min (98). These studies imply that increasing short rest between set durations will increase reps/set, larger increases in duration are likely to result in larger increases in reps/set, and the largest increases in reps/set are likely to occur when increasing from short (&lt; 1 min) to moderate (2 min), or short to long (&gt;3 min) rest between set durations.
<h3>Moderate Rest Between Set Durations</h3>
A few studies have compared moderate rest between set durations. Tibana et al. compared 12 resistance-trained men (age: mean 23.05 age) performing moderate (1.5 min and 2 min) rest between sets during leg curls, for 3 sets/exercise, 90% 1-RM loads, reps to failure/set, with a moderate tempo (3-4 sec/rep). The findings demonstrated that both groups performed a similar number of reps/set during the 2nd and 3rd sets, and similar exercise volume; however, the shorter rest between set duration resulted in a significant increase in the rate of perceived exertion during the 2nd set (99). Mirzaei et al. compared 18 resistance-trained men (age: 22.67 &#xB1; 1.94 years) performing moderate (1.5 min and 2.5 min) and long (4 min) rest between set durations, with both 60% and 90% of 1-RM loads, during squats, for 4 sets/session, reps until failure/set, and a moderate tempo (3:0:1). The findings demonstrated that longer rest between sets resulted in more reps/set for sets 2-4, an increase in exercise volume, and the increase was demonstrated with both loads. Note, the difference in reps/set and exercise volume for moderate (1.5 and 2.5 min) rest between set durations did not reach statistical significance (100). Rahimi et al. (2009) compared 15 resistance-trained men (age: 21 &#xB1; 2.1) performing short (1 min), and moderate (1.5 min and 2 min) rest between set durations during bench press, 4 sets/exercise, 12-RM loads, reps until failure/set, with a moderate (2:0:1) tempo. The results demonstrated that shorter rest periods resulted in fewer reps/set and less total exercise volume; and further, that the difference between 1 min and 1.5 min rest was not as significant as the difference between 1.5 min and 2 min rest between sets (101). These studies suggest that comparing moderate rest between set durations (1 min - 2.5 min) may result in relatively small improvements in reps/set and exercise volume; however, increasing from moderate to long rest between sets result in significant increases.
<h3>Comparing Short, Moderate, and Long Rest Between Sets</h3>
Several studies have compared short, moderate, and long rest between set durations. Senna et al. (2009) compared 14 resistance-trained men (age: 23.0 &#xB1; 2. 2) performing moderate (2 min) and long (5 min) rest between sets during a lower body resistance training routine (leg press, leg extensions and leg curls), 3 sets/exercise, 10-RM load, reps until failure/set, with no attempt to control movement velocity. The findings demonstrated that moderate (2 min) rest between set durations resulted in a significant reduction in reps performed during 2nd and 3rd sets, resulting in reduced exercise volume (102). Another study by, Senna et al. (2015) compared 14 resistance-trained men (age: 20.93 &#xB1; 2.40 years) performing short (1 min), moderate (2 min), and long (3 min and 5 min) rest between set durations with either bench press or machine chest flyes, 3 sets/session, 10 RM loads, with reps until failure/set. Findings demonstrated that long (3 min and 5 min) rest between set durations resulted in similar reduction in reps during subsequent sets of the bench press exercise; however, significant differences were noted for all rest interval lengths for the chest fly (103). A third study by&#xA0;Senna et al. (2016) compared 10 resistance-trained men (age: 24.3 &#xB1; 2.8 yrs) performing short (1 min), moderate (2 min) and long (4 min) rest between set durations during chest flyes or bicep curls, for 3 sets/exercise, 10 RM loads, reps until failure/set, with no attempt to control movement velocity. The findings demonstrated that shorter rest periods resulted in a larger decrease in the number of reps/set during sets 2 and 3, for both exercises (104). Willardson et al. compared 15 resistance-trained men (age 20.73 &#xB1; 2.60 years) performing short (1 min), moderate (2 min), and long (5 min) rest between sets during squats and bench press (5 minutes rest between exercises), 4 sets/exercise, 8-RM loads, reps until failure/set, with a moderate rep tempo (3:0:1). The findings demonstrated a significant difference between all rest between set durations, with shorter rest periods resulting in a significant reduction in reps/set for sets 2-4 (105). Another study by Willardson et al. compared 16 resistance-trained men (age: 26.75&#xA0; &#xB1; 6.40 years) performing short (1 min), moderate (2 min), and long (3 min) rest between sets during bench press, 2 sessions/week, 5 sets/session, reps to failure/set, 1st session/week with 80% of 1-RM, and the 2nd session/week with 50% of 1-RM. The study demonstrated that longer rest periods resulted in significant improvements in the ability to maintain rep/set with additional sets, and the results were similar for 50% and 80% of 1-RM loads (106). Hernandez et al. compared 15 resistance-trained males (age: 26 &#xB1; 5 years) performing moderate (2 min) and long (5 min and 8 min) rest between set durations, while performing a bench press for 4 sets, 85% of 1-RM load, reps to failure/set, with no attempt to control rep tempo. The findings demonstrated that reps for sets 2-4 decreased significantly less following longer rest between set durations (107). Rahimi et al. (2005) compared 20 resistance-trained men (age 20.73 &#xB1; 2.60 years) performing short (1 min), moderate (2 min) and long (5 min) rest between set durations during squats for 4 sets/exercise, 85% of RM loads, reps until failure/set, with a moderate rep tempo (3:0:1). Again, the findings demonstrated that reps/set for sets 2 - 4 was significantly higher for the long rest between sets group; however, this study did not demonstrate a significant difference between short (1 min) and moderate (2 min) rest between set durations (108). An RCT by Kassiano et al. compared 20 resistance-trained young women (age: 21.1&#xB1;2.6 years) performing short (1 min), moderate (2 min) or long (3 min) rest between sets of 45&#xB0; leg press, for 5 sets, reps to failure/set, moderate tempo (2:0:2), and loads of 60%, 65%, 70%, 75%, and 80% of 1RM. The findings demonstrated that the total reps/set for subsequent sets increased with longer rest periods. Rate of perceived exertion was higher during the 1 min rest period session, but the difference was small and statistically insignificant (109).&#xA0;These studies demonstrate that the decrease in reps/set during additional sets is likely to be reduced by longer rest between set durations. However, these studies suggest that statistically significant differences may not be achieved when comparing short and moderate rest between set durations with a difference of less than 1 min, or long rest between set durations with a difference of less than 2 minutes.

Gender and age may have an influence on rest between set duration recommendations. Faigenbaum et al. compared 12 boys (age: 11.3 &#xB1; 0.8 yr) and 17 men (age: 21.4 &#xB1; 2.1 yr) performing short (1 min), moderate (2 min), and long (3 min) rest between sets during bench press for 3 sets, 10-RM loads, and reps until failure/set. The findings demonstrated that men performed significantly more reps/set following longer rest periods, and boys exhibited smaller decreases in reps/set with additional sets and/or shorter rest between sets (110). Ratamess et al. compared resistance-trained participants including 11 men (22.8 &#xB1; 6.5 years) and 11 women (age: 20.8 &#xB1; 4.5 years), and a second <a id="cohort-study" data-tip="1416" target="_blank" href="/glossary-term/cohort-study" class="glossary">cohort</a> of 23 men (age:: 21.8 &#xB1; 3.1 years) divided into stronger and weaker groups (based on 1-RM bench press strength), while performing short (1 min), moderate (2 min) and long (3 min) rest between sets during bench press for 3 sets, up to 10 reps/set, with 75% of 1-RM loads. The findings demonstrated that longer rest between set durations resulted in more total reps (as well as higher average velocity and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>), and that women and weaker men performed more repetitions than strong men, exhibited a less significant decrease in reps/set with shorter rest between set durations, and were better able to sustain reps/set with additional sets (111). Davo et al. compared 38 resistance-trained participants (18 men and 20 women, age: 18+ years) divided into stronger and weaker groups based on peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> output, while performing short (1 min), moderate (2 min), and long (3 min) rest between set durations during bench press throws, for 5 sets/session, 8 reps/set, 40% of 1-RM load. The findings demonstrated that all groups exhibited a significant decrease in <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> during subsequent sets with 1 min rest periods, stronger individuals could maintain <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> with 2 min rest periods, and weaker individuals needed at least 3 min rest to maintain <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>. Further, post-exercise serum lactate and delayed onset <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> soreness (DOMS) was higher for weaker groups and longer rest periods; however, rate of perceived exertion during exercise was higher with shorter rest periods (112). These studies suggest that compared to weaker individuals, stronger individuals may be able to better maintain reps/set for a 2nd set with shorter rest periods; however, beyond a 2nd set it appears that stronger individuals may also benefit from longer rest between set durations. Stronger individuals can also maintain peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> output with moderate (2 min) rest between sets, whereas weaker individuals need long (3 min) rest between sets. Females and adolescents may be better able to maintain reps/set with shorter rest between set durations; however, they are less likely to maintain peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>. Although this would be a topic for a different review, it may be hypothesized that strength training results in a larger disparity between maximal strength and strength endurance; for example, strength training would increase the difference in load between an individual&apos;s 1-RM and 10-RM. This could be a contributing factor to females and adolescents exhibiting higher resistance to fatigue.

These two paragraphs may be the most important findings of this review. The studies covered suggest that the duration of rest between sets should NOT be based on training goal, intensity, or exercise selection. Instead, the <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> rest between set duration should be based on volume; specifically the number of sets/exercise, and potentially the number of reps/set. In short, previous recommendations regarding the duration of rest between sets have been based on the wrong variable.
<h3>Load and Rep Range</h3>
Two studies suggest that longer rest between set durations should be recommended with more reps/set, or sets/exercise, but recommendations may not be influenced by larger loads. Scudese et al. compared 16 trained men (age: 23.75 &#xB1; 4.21 years) performing short (1 min), moderate (2 min), and long (3 min and 5 min) rest between set durations, during bench press, 4 sets/session, 3-RM loads, with reps until failure/set, and no attempt made to control rep tempo. The findings demonstrated that the short (1 min) rest between set durations resulted in significantly less reps in subsequent sets, starting with set 2, and resulted in less total volume of exercise. Further, there was no significant difference between moderate (2 min), and long (3 min and 5 min) rest between set durations, which resulted in a reduction in reps/set only for sets 3 and 4 (113). Senna et al. (2017) compared 16 resistance-trained men (age: 20.75 &#xB1; 2.54 years) performing short (1 min), moderate (3 min), and long (5 min) rest between set durations, with either 50% or 80% of 1-RM loads, during triceps pull-downs, 4 sets/exercise, reps until failure/set, with no attempt to control rep tempo. The findings demonstrated that when performing reps until failure/set with 80% of 1-RM loads, short (1 min) rest between sets resulted in a significant reduction in reps during subsequent sets and total volume of exercise when compared to longer rest between sets; however, 3 min and 5 min rest between sets resulted in similar reps/set and volume of exercise. When performing reps until failure/set with 50% of 1-RM loads, the number of reps/set and volume of exercise was increased with longer duration reps between sets, including a significant difference between 3 min and 5 min rest between sets (114). These studies suggest that longer rest between sets may have a larger influence on endurance strength training (lower loads and higher rep ranges) than maximum strength training (higher loads and lower rep ranges). It may be reasonable to conclude that very long (&gt; 3 min) rest between set durations are only necessary when performing multiple high rep sets (&gt; 15 reps), or more than 4 sets/exercise.
<h3>More Sets Requires More Rest</h3>
Additional studies suggest that rest between set recommendations should be influenced by the number of sets/exercise. Richmond et al. compared 28 resistance-trained men (age: 21.5 &#xB1; 3.2 years) performing short (1 min) or long (3 min and 5 min) rest between set durations, during bench press, for 2 sets/session, 75% of 1-RM load, and reps until failure/set. The findings demonstrated that reps decreased significantly during the 2nd set with short (1 min) rest between sets; however, reps/set were maintained during a 2nd set with long (3 min and 5 min) rest between set durations (115). Monteiro et al. compared 25 recreationally active men (age: 26.84 &#xB1; 4.59 years) performing short (1 min), moderate (2 min), and long (3 min and 5 min) rest between sets, during bench press for 7 sets, 10 RM load, reps until failure/set, with no attempt to control rep tempo. The findings demonstrated that shorter rest periods resulted in less reps performed during additional sets, less total reps/session, and an increased rate of perceived exertion. Interestingly, there was no difference in 2nd set performance between short (1 min) and moderate (2 min), or long (3 min and 5 min) rest between set durations (116). Miranda et al. (2007) compared 14 resistance-trained men performing short (1 min) or long (3 min) rest between sets during a routine of 6 upper body exercises (wide grip lat pull-down, close grip pull-down, machine seated row, barbell row lying on a bench, dumbbell seated arm curls, and machine seated arm curls), for 3 sets/exercise, 8-RM loads, reps until failure/set, and no attempt made to control rep tempo. The findings demonstrated that the long (3 min) rest between sets resulted in more reps/set and total exercise volume; and further, that the difference in the number of reps/set was significantly larger for the 3rd set (117). An RCT by Garc&#xED;a-L&#xF3;pez et al. compared 21 untrained individuals (age: 25 &#xB1; 5 years) performing no exercise (controls), short (1 min) or long (4 min) rest between sets of machine biceps curls for 5 weeks, 2x/week, 3 sets/exercise, 60% of 1-RM loads (increased 5% in weeks 3, 4 and 5), reps until failure/set, and a tempo including a maximum velocity concentric contraction (maxV). The findings of the study demonstrated that the long rest between sets group was able to complete similar reps/set for sets 1 and 2, with a small decrease in reps during set 3, and the short rest between sets group exhibited a significant decrease in reps/set during sets 2 and 3 (90).&#xA0;Senna et al. (2011) compared 15 resistance-trained men (age: 23.6 &#xB1; 2.64 years) performing short (1 min) or long (3 min and 5 min) rest between set durations, during bench press, chest flyes, leg press and knee extensions, each for 5 sets, 10 RM loads, reps to failure/set, with a self-paced slow controlled tempo. Findings demonstrated that the long (3 min and 5 min) rest between set durations resulted in similar reduction in reps during subsequent sets of the bench press exercise. However, for all other exercises, significant differences were noted when comparing short (1 min) and long (3 min and 5 min) rest between set durations, with short (1 min) rest resulting in a decrease in reps by the 2nd set, long (3 min and 5 min) rest resulting in a decrease by the 3rd set, and the most total reps performed with the long (5 min) rest between set duration (118). These studies suggest that the recommended rest between sets should be determined by the number of sets/exercise performed. Generally, moderate rest between set durations (2 min) are likely sufficient if performing 2 sets/exercise, long rest (3 min) sufficient for 3 sets/exercise, and longer rest (&gt; 4 min) only recommended when performing 4 sets or more/exercise.&#xA0; &#xA0;

A study by de Salles et al. may imply key variables that contribute to a lack of statistically significant differences in strength following training with different rest between set durations. de Salles et al. compared 36 recreationally-trained men (age: 22.4 &#xB1; 1.3 years) performing short (1 min) or long (3 min and 5 min) rest between sets during a resistance training (split-routine) program (Program A: barbell bench press, barbell incline press, pronated wide grip lat pull-downs, supinated close grip lat pull-downs, barbell overhead press, barbell biceps curls, pulley triceps extensions, and abdominal crunches, and Program B: 45&#xB0; degree angled leg press, hack squat machine, leg extension machine, leg curl machine, and seated calf machine), for 16 weeks (64 sessions), 4x/week (each routine 2x week), 3 sets/exercise, reps until failure/set, with 4-6 RM and 8-10 RM loads. The findings demonstrated that when compared to short rest between set durations, longer rests resulted in significantly larger volumes of exercise, and larger increases in bench press and leg press 1-RM strength. Further, although improvements were similar for 3 min and 5 min rest between set durations when tested following 8 weeks of training, the 5 min rest between set duration resulted in significantly larger increases in strength following 16 weeks of training (119). This study may imply two important relationships to consider when researching rest between set durations. First, it may be likely that improvements in training resulting from an increase in rest between set duration length, will be much larger when increasing from short to moderate or short to long rest between set durations. For example, increasing from 30 sec to 1 min rest between sets, or from 1 min to 3 min rest between sets, is likely to result in more improvement than increasing from 3 min to 5 min rest between sets. Second, because of the diminished effects of increasing the duration of long rest between sets (e.g. from 3 min to 5 min), it is likely that differences will require longer training periods (more than 8 weeks) to reach statistical significance.

Variable Rest

Several studies have compared self-selected versus pre-determined rest between set durations. Goessler et al. compared 10 physically active men (age: 23 &#xB1; 2 years) performing short (1 min), long (2 min), and self-selected (157 &#xB1; 37 seconds) rest between set durations during a resistance training routine (bench press, smith machine squats, bicep curls, and leg curls), for 3 sets/exercise, 75% of 1-RM loads, and reps until failure/set. The study demonstrated that short (1 min) rest between set durations resulted in significantly less reps/set during 2nd and 3rd sets, and a reduction in exercise volume. Statistically, the self-selected and moderate (2 min) rest between set protocols were similar length, and they resulted in similar reps/set and exercise volume (120). De Salles et al. compared 27 healthy subjects (age: 26 &#xB1; 1.5 years) performing moderate (2 min) or self-selected rest between set durations during a resistance training routine (squats, leg press, bench press, bicep curls), 3 sets/exercise, 75% of 1-RM load, reps to failure/set, with no <a id="specificity" data-tip="1224" target="_blank" href="/glossary-term/specificity" class="glossary">specific</a> rep tempo. Self-selected rest between sets varied by set and exercise, with the longest average rest between the 1st and 2nd sets of leg press (130.73 &#xB1; 35.40 sec), the shortest rest between the 1st and 2nd sets of bicep curls (101.08 &#xB1; 34.15 sec), and the average rest between sets for all exercises likely close to 2 min. The findings demonstrated that both rest between sets protocols resulted in similar reps/set and total exercise volume (121). Ibbott et al. compared 16 resistance-trained athletes performing long (3 min and 5 min) and self-selected (approximately 3.5 - 4.5 min) rest between sets during a heavy lower body resistance training routine, 5 sets/session, and 5 reps/set. The findings demonstrated that all conditions resulted in similar decreases in EMG activity, decreases in velocity, and increases in perceived exertion with additional sets (42). Cardozo et al. compared 16 young male football players (age: 19.8 &#xB1; 0.9 years) performing short (1 min), long (3 min), or self-paced rest between set durations during a routine performed in order and in reverse order (bench press, back squat, biceps curl, and plantar flexion). The findings demonstrated that a larger volume of exercise was performed for exercises at the beginning of a routine and that both self-selected and long rest between sets resulted in a larger volume of exercise than short rest between sets (93). Sim&#xE3;o et al. compared 33 resistance-trained men (age: 21.4 &#xB1; 2.5, range 20.2&#x2013;23.2) performing moderate (75 sec) or self-selected (average 90 -135 sec) rest between sets during an upper body resistance training routine (bench press, lat pulldowns, shoulder press, and seated rows) for 8 weeks, 3 sets/exercise, 75% of 1-RM, reps until failure/set, and no attempt to control rep tempo. The self-selected rest between sets ranged from 90 - 135 sec, and the length of each rest period increased with additional sets. The findings demonstrated that the self-selected rest period group performed more reps/set for every set after the second set of bench press; however, strength gains were similar at the end of 8 weeks (66). These studies demonstrate that self-selected rest between set durations are likely to result in similar reps/set and exercise volume, as the equivalent pre-determined rest between set duration. Self-selected rest between set durations likely only increase reps/set and exercise volume when they are longer than pre-determined durations.

Additional studies have compared pre-determined and heart rate based rest between set durations. Larson et al. compared 15 recreationally trained college males (age: 28.3 &#xB1; 1.2 years) performing timed (3 min), work:rest ratio based (1:3 ratio), or heart rate based (return to 60% of age predicted HR max) rest between set durations, during squats, 4 sets, 85% of 10-RM load, reps until failure/set, and a slow tempo (2:0:3). The study demonstrated that all 3 rest conditions resulted in similar reps/set, volume of exercise, post-exercise plasma blood lactate concentrations, and rate of perceived exertion; despite the duration between sets increasing for the HR group, decreasing for the work:rest ratio group, and staying the same for the timed group (122). Piirainen et al. compared 24 novice male exercisers performing moderate (2 min) rest between sets, or a heart rate (HR) mediated rest between sets time (average = 54 sec.), during 7 weeks of resistance training, 3x/week, 3 sets/exercise, 10 RM loads, with reps until failure/set. The study demonstrated that the HR mediated rest between sets protocol resulted in a decrease in reps/set and exercise volume; however, 1-RM and 10-RM strength increased similarly for both groups following the 7 weeks of training (67). Buskard et al. compared 34 recreationally trained college males (age: 22.7 &#xB1; 3.5 years) performing short (1 min) or heart rate based (1 - 3.5 min) rest between set durations during bench press, with sets performed until participants could not perform at least 8 reps/set, with 60% of 1-RM load, and a moderate tempo (1:1:1). The study demonstrated that heart rate based rest between sets resulted in 40% more reps performed per session, including an increase in reps/set and sets/session (123). These studies likely demonstrate that heart rate is not as influential as the actual length of the rest between set duration, and regardless of heart rate, longer rest between sets will likely increase reps/set and exercise volume.
<img title="Image of the body&apos;s heart rate control system " src="https://www.datocms-assets.com/25800/1653665887-heart-rate.jpg" width="213" height="398" alt="The heart rate control system">

Variable rest is a topic that should be investigated further. As mentioned above, Sim&#xE3;o et al. compared moderate (75 sec) and self-selected (average 90 -135 sec) rest between set durations, noting that the self-selected rest between set duration increased with additional sets and resulted in more reps/set performed for every set after the second set (Note, strength gains were similar at the end of 8 weeks (66). Another study mentioned above, Buskard et al. compared 34 recreationally trained college males (age: 22.7 &#xB1; 3.5 years) performing short (1 min) or heart rate based (1 - 3.5 min) rest between set durations during bench press, with sets performed until participants could not perform at least 8 reps/set, with 60% of 1-RM load, and a moderate tempo (1:1:1). The duration of heart rate based rest between sets gradually increased and resulted in 40% more reps performed per session, including an increase in reps/set and sets/session (based on the criteria above) (123). Dehnou et al. compared 16 resistance-trained men (age: 27 &#xB1; 8.08 years) performing constant (90-90-90 sec), decreasing (120-90-60 sec) and increasing (60-90-120 sec) rest between sets during bench press, 4 sets/session, 80% 1-RM load, reps until failure/set, with no attempt to control movement velocity. The findings demonstrated that all protocols resulted in a similar decrease in reps during set 2, constant and decreasing rest periods resulted in similar decreases in reps with each additional set, and increasing rest periods results in similar reps performed for sets 2-4 (no significant decrease) (124). These studies suggest that incremental increases in rest between set duration with each additional set may aid in maintaining reps/set; however, further research is needed to compare incremental increases with long rest between set durations.

Inter-set Rest (a.k.a. Cluster Sets, Rest Redistribution, or Rest Between Reps)

Another rest strategy is a combination of rest between sets and between reps during sets. Stone et al. compared 8 resistance-trained men (age: 24 &#xB1; 3 years) performing back squats with 80% of 1-RM loads, and a conventional routine of 4 sets, 6 reps/set, and moderate (2 min) rest between sets, or a rest-redistribution routine (cluster sets) of 4 sets,&#x2009;2&#x2009;&#xD7;&#x2009;3 reps with 30 sec rest between reps, and moderate (90 sec) rest between sets. The findings demonstrated that sagittal and frontal plane kinematics were similar for both protocols. During the conventional routine hip <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> increased and knee <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> decreased from reps 1-6 with additional sets, and during the rest redistribution routine hip <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> increased, and knee <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> decreased from reps 1-3 and then reset to original value during rep 4. Additionally, the rest-redistribution protocol resulted in greater mean <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> per set (125). Merrigan et al. compared 12 resistance-trained female college athletes (age: 18 - 35 years) performing moderate (2-min) rest between sets or a rest-redistribution protocol of 30 sec rest after the 5th rep, and a moderate (90 sec) rest between sets during back squats (to parallel), for 4 sets, 10 reps/set, 70% of 1-RM loads, with each concentric repetition performed &quot;as explosively as possible&quot;. The findings demonstrated that the rest redistribution protocol improved maintenance of velocity and peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> for reps 7-9, and for sets 2-4 (126). Salvador et al. compared 8 resistance-trained participants (age: 23 &#xB1; 1 years) performing a conventional protocol of 4 sets, 10 reps/set, and moderate (120 sec) rest between sets, to a rest-redistribution protocol of 4 sets, 2 x 5 reps/set, 30 sec rest between reps, and moderate (90 sec) rest between sets, while performing barbell back squats, with 70% 1-RM loads, and equal volumes. Findings demonstrated that the rest-redistribution protocol resulted in higher average velocity, greater peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, and slightly lower rate of perceived exertion during subsequent sets (17). Last, Moro et al. compared the legs of 9 healthy participants performing leg extensions with a &quot;high-intensity interval protocol&quot; of 3 sets, 6-RM loads, 6 + 2 or 3 reps/set (until fatigue), 20 sec rest between reps, and long rest between sets (2.5 min), and a &quot;conventional resistance routine&quot; of 3 sets, 15 reps/set, moderate (75 sec) rest between sets on the other leg. Findings from <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> biopsy, western blot, and real-time polymerase chain reaction messenger RNA (mRNA) analysis,&#xA0; demonstrated that conventional resistance training resulted in larger increases of AMPK phosphorylation at 24 hours, and a significant difference in post-exercise striated <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> activator of Rho signaling. Note, although these findings may have implications for hypertrophy training, it is important to note that the majority of indicators of anabolic and metabolic response were similar for the two protocols (127). These studies suggest that rest redistribution protocols may be beneficial for maintaining peak and mean velocity/power during reps in the second half of a set, and/or during additional sets; however, conventional rest between sets protocols may result in larger increases in some markers of protein synthesis.

Additional studies may aid in improving rest-redistribution recommendations. Wongsason et al. compared 30 competitive male rugby players (age: 20.00 &#xB1; 0.61 years) performing long (4 min) rest between sets, and long (4 min) rest between sets with 15 sec rest following every 5th rep, during jump squats, for 6 weeks, 3 sets/session, 30 reps/set, 20% of 1-RM load. The findings demonstrated that the rest between every 5th rep group exhibited significantly larger improvements in rate of force development, peak force, peak velocity, and peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> (78). Ho et al. compared 34 college-aged men performing inter-set rest protocols, including no rest, 20 sec, and 40 sec rest, between reps 3 and 4 during bench press, for 3 sets, 3+3 reps/set, 6 RM loads, with rest between sets equated to ensure total rest for each protocol was similar. The findings demonstrated that 20 and 40 second rest between reps interval resulted in similar improvements in failure rates and reps completed for sets 2 and 3, and the 40 sec rest only improved rate of perceived exertion during the 3rd set (128). These studies suggest that short (20 sec) rest between reps is sufficient (no additional benefits with 40 sec) to improve force, velocity, and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> during the second half of sets.

Two studies compared inter-set rest protocols to other unconventional protocols (half reps and rest, and drop sets). Jukic et al. compared 26 resistance-trained men (amateur weightlifters and track and field athletes, age; 28 &#xB1; 5.4 years) while performing a conventional protocol of 3 sets, 10 reps/set, 70% of 1RM, with long (4 min) rest between sets, and a &quot;rest redistribution protocol&quot; of 5 sets, 6 reps/set, 70% 1RM, with moderate (2 min) rest between sets. Participants were asked to perform the most &quot;explosive&quot; concentric contraction possible, with a controlled, self-mediated eccentric tempo. The findings demonstrated that <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> and velocity of repetitions were similar for both protocols; however, the rate of perceived exertion was lower for the &quot;rest redistribution protocol&quot;. This study, may suggest that adding short rests between reps of a single set is different than halving long rest periods and reps/set (129). Enes et al. compared 28 trained males (age: 18&#x2013;30 years) performing work-matched protocols including rest between reps, drop-sets, and conventional rest between sets. The same lower body resistance training routine was used for all protocols (barbell back squat, 45&#xB0; leg press, seated knee extension, stiff-leg deadlift and seated knee flexion) and performed for 8 weeks, 2x/week; the drop set protocol included 3 sets, 10+6 reps/set, 75% and 55% of 1-RM, and a moderate (2 min) rest between sets; the inter-set rest interval protocol included 3 sets, 10+6 reps/set, 75% of 1-RM, a moderate (2 min) rest between sets, and a 20 sec rest between reps interval; the traditional protocol included 4 sets, 12 reps/set, 70% of 1-RM, and a moderate (2 min) rest between sets. The findings demonstrated that all protocols improved strength and resulted in similar increases in quadriceps CSA; however, the rest between reps protocol resulted in the largest improvements in strength (130). These studies suggest that rest between reps protocols may be more beneficial than halving rest between sets and reps/set, drop sets, and conventional rest between sets protocols, for improvements in maximal strength and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>.

Frequent rest between rep periods have been compared to conventional rest between sets protocols. Another study by Merrigan et al. compared 11 resistance-trained men (age: 26.0 &#xB1; 1.8 years) performing a conventional protocol of 4 sets, 10 reps/set, with 3 moderate duration (95 sec) rest periods, and a rest redistribution protocol of 20 sets, of 2 reps, with 20 short (15 sec) rest periods. Both protocols included 40 total reps and 285 sec rest, were performed with an isokinetic eccentric knee extension machine, from 10-90&#xB0; of knee flexion with a velocity of 60&#xB0;/sec, and the machine actively returned the leg back to the starting position (no concentric <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> actions). The findings demonstrated that peak <a id="torque" data-tip="1294" target="_blank" href="/glossary-term/torque" class="glossary">torque</a> and total work were the same for both protocols; however, the rest redistribution protocol resulted in greater average <a id="torque" data-tip="1294" target="_blank" href="/glossary-term/torque" class="glossary">torque</a> (especially during later repetitions), significant improvements in <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> oxygenation, and a small but significant reduction in rate of perceived exertion (131). Zaras et al. compared 16 physical education students (age: 23.6 &#xB1; 6.8 years) performing continuous (conventional) reps/set, or resting for 20 sec between each rep, during leg press for 7 weeks, 2x/week (72+ hours between sessions), for 4 sets, 6 reps/set, 85% of 1-RM load, and long (3 min) rest between sets, without the intent to produce maximum velocity with each rep. The findings demonstrated that strength and quadriceps CSA increased similarly for both groups; however, the rest between reps group exhibited larger increases in rate of force production and vastus lateralis fascicle length. This may suggest that rest between reps is advantageous for <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> development (132). Garc&#xED;a-Ramos et al. compared 34 physically-active male college students (age: 22-33 years) performing continuous, 6 sec, or 12 sec rest between rep durations, during smith machine explosive bench press throws with 30%, 40%, and 50% of 1-RM loads. The reduction in bar velocity was significantly less for the 12 sec rest protocol when compared to the 6 sec rest and continuous protocols. Additionally, the recommended duration of rest between reps may be determined by load and reps/set, as the continuous and 6 sec. rest protocols resulted in similar bar velocities until the 7th rep with 30% - 40% of 1-RM loads, and until rep 5 with 50% of 1-RM loads (133). Prestes et al. compared 18 resistance-trained participants (age: 30.3 &#xB1; 6.5 years, 14 men and 4 women) performing a conventional protocol including long (2-3 min) rest between sets, 3 sets/exercise, 6 reps/set, 18 total reps, with 80% of 1-RM loads, or a rest between reps protocol of 80% of 1-RM, 20 sec rest/reps for 18 total reps (2-3 min rest between exercises). Both groups trained for 6 weeks, 4 sessions/week, using a 2-day split routine (Session 1: barbell bench press, dumbbell incline press, cable cross, military presses, <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> raises, tricep pulleys, and barbell triceps extensions; Session 2: Squats, 45&#xB0; leg press, leg curls, front lat pull-downs, seated rows, dumbbell <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> rows, standing barbell elbow curl, and preacher curls). The findings demonstrated that both groups exhibited similar improvements in 1-RM strength, and chest and arm cross-sectional area (CSA); however, the inter-rep rest group exhibited larger improvements in <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> endurance (number of reps with 60% of 1-RM load) and thigh CSA (134). When compared to conventional rest between sets protocols, these studies suggest that frequent short rest between reps may be beneficial for preserving peak force and <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> during the later reps of a set. Further, longer rest between reps may be beneficial as reps/set and loads increase, and frequent rest between reps may improve outcomes related to <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> endurance.

Circuit Training

<h3>Is Circuit Training the Answer?</h3>
The research discussed in this review demonstrates that long (&gt; 3 min) rest between set durations are <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> for the majority of resistance training goals, likely due to the resulting increase in reps/set and exercise volume. These studies assume that any increase in session time is reasonable; however, nearly all exercisers (recreational to professional athletes) have limited time or would benefit from less time spent per session. This leads to the question of whether opposing or less related <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> groups, can be trained during long rest between sets, and/or if &quot;circuit training&quot; (sometimes referred to as &quot;vertical loading&quot;) is a viable option to ensure <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> volume is achieved within limited session times. After a comprehensive review of &quot;circuit training&quot; research, only a handful of studies could be located that directly compared similar routines with conventional and circuit training protocols. These studies are discussed below.
<h3>Comparing Circuit Training and Conventional Strength Training</h3>
Research has compared strength training with conventional long (&gt; 3 min) rest between sets and circuit protocols with short (30 - 60 sec) rest between exercises. Alcaraz et al. compared 10 resistance-trained men (age: 26 &#xB1; 1.6 years) performing bench press, for 5 sets, reps until failure/set, 6 RM load, long (3 min) rest between sets, and a moderate tempo (3:0:maxV), to heavy circuit training (bench press, leg extension, ankle extension) for 5 sets/exercise, reps until failure/set, 6 RM loads, short (35 sec) rest between exercises, 3 min of active rest between circuits, with a moderate tempo (3:0:maxV). The findings demonstrated that despite heart rate being higher during heavy circuit training, both groups performed the bench press exercise with a similar number of reps/set, peak, and average bar velocity, and peak and average <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> (135). Another study by Alcaraz et al. (an RCT) compared 38 resistance-trained men (age: 22.7 &#xB1; 3.3 years) performing traditional strength training or heavy circuit training including 6 exercises (2 blocks including block 1: pec deck, knee extensions, elbow flexion, and block 2: knee flexions, lat pulldowns, and ankle extensions) for 8 weeks, 3x/week, 3-6 sets/exercise, and 6-RM loads (~85&#x2013;90% of 1-RM), and a moderate tempo (3:0:1). The conventional resistance training protocol included 3 min rest between sets and 5 min rest between blocks, and the circuit training protocol included 35 sec rest between exercises, and 5 min rest between blocks. Research demonstrated that improvements in lean body mass, 1-RM strength, peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, and shuttle run performance were similar for both groups (136). Johnson et al. compared 39 high school football athletes (age: 16 &#xB1; 2 years) performing conventional or circuit protocols with the same routine comprised of Olympic lifts and strength exercises (e.g. Day 1: hang clean, <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> jerk, bench press, dumbbell split squat, inverted rows) for 6 weeks, 3x/week, 3 sets/exercise, 8 reps/sets, with rest between sets not tightly controlled. Note, both groups performed hang-cleans prior to the rest of the routine for 3 - 5 sets/session, 1-5 reps/set, with conventional rest between sets. The findings demonstrated that the groups were not equal at the beginning of the training program; however, it is likely both protocols had similar efficacy for improving strength, <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, and agility. Due to the circuit group starting with more strength and making similar improvements, it may be hypothesized that the circuit protocol was more effective (137). These studies suggest that conventional (long rest between sets) and circuit (short rest between exercises) protocols of strength training are likely to result in similar reps/set, power/rep, and exercise volume during sessions, and similar improvements in lean body mass, maximum strength, <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>, and agility following weeks of training.
<img title="A challengeing transverse abdominis progression used to target core stability" src="https://www.datocms-assets.com/25800/1649282054-quadruped-in-class.jpg" alt="TVA training in a group class">

Conventional and circuit training protocols have been compared with consideration of the effects on VO2 Max, heart rate, energy consumption, and lactate. Messier et al. compared 36 male college students, who had not engaged in a running or resistance training program in the previous 4 months, following performance of a Nautilus machine circuit, conventional resistance training, or a running program for 10 weeks, 3 days/week. The Nautilus machine circuit included 12 exercises (hip and back, leg extensions, leg press, leg curls, pullovers, torso arms, flyes, decline press, <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> raises, shoulder press, bicep curls, and triceps extensions), for 1 set/exercise, 8-12 reps until failure/set for upper body, 15 -20 reps until failure/set for lower body, and no rest between exercises. The conventional resistance training program included 8 exercises (squats, stiff-legged deadlifts, lunges, bent-over rows. chest flyes, bench press, military press, bicep curls, triceps extensions), for 3 sets/exercise, 6 reps/set, 75% of 1-RM loads, and 15:30s work:rest ratio. And, the running program was performed for approximately 30 min/session, with a progressive increase in intensity, and 60-90% of heart rate reserve (HRR). The findings demonstrated that circuit training resulted in similar increases in VO2 max and strength as the conventional resistance training program, but did not achieve the improvements in VO2 max of the running program (138). Deminice et al. compared 11 resistance-trained male participants (age: 25.9 &#xB1; 2.8 years) performing a strength training routine of 6 exercises (bench press, leg extensions, cable pull-downs, leg flexions, overhead press, leg press) with either a conventional resistance training protocol of 3 sets/exercise, 10 reps/set, 75% of 1-RM loads, and moderate (90 sec) rest between sets, or a circuit resistance training protocol of 3 sets/exercise, 10 reps/set, 75% of 1-RM loads, with no rest between 2 exercises for different muscles. The findings demonstrated that both protocols resulted in a similar number of reps/set, total exercise volume, blood lactate, and rate of perceived exertion, despite circuit training taking half the time (20 min compared to 40 min), and resulting in higher peak and average heart rates during training. Note, the conventional training protocol resulted in higher post-exercise serum concentration of thiobarbituric acid reactive substances (TBARSs), glutathione (GSH), creatine kinase (CK), and uric acid (139). An RCT by Brentano et al. compared 28 postmenopausal women divided into a control group, conventional strength training group, and circuit training group, for&#xA0;24 weeks, 3x/week, with a linear increase in loads (1-RM tested every 8 weeks), and similar routines (alternating upper and lower body exercises including leg press, hip abductions, hip adductions, knee extensions, chest flyes, reverse flyes, arm curls, triceps push-downs, sit-ups, and back extensions). The circuit training protocol included 10-20 reps/set, 45-60% of 1-RM loads, 2-3/exercises, and no rest between exercises; the strength training protocol included 6-20 reps/set, 45-80% of 1-RM loads, 2-4/exercise, and moderate (2 min) rest between sets. The findings demonstrated that the traditional strength training and circuit training protocols resulted in similar increases in VO2 max, similar maintenance of bone mineral density, and significant increases in <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> strength and endurance. The strength training protocol resulted in slightly larger increases in lower body strength and EMG activity following training (140). These studies suggest that conventional (long rest between sets) and circuit (short rest between exercises) protocols of strength training may result in similar reps/set, exercise volume, rate of perceived exertion, energy consumption, cardiovascular benefits, and <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> strength/endurance; despite circuit training resulting in higher peak and average heart rates. Some evidence suggests that conventional strength training may result in slightly higher post-exercise serum concentrations of markers correlated with <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> damage, and slightly larger increases in lower body strength.

One study was located comparing the amount of rest between exercises during circuit training. Gordon et al. compared 12 physically active men (age: 28 &#xB1; 5 years) performing two protocols with different rest between set durations and different volumes, but performed in the same total time. The 1st protocol included 30 sec/set, 30 sec rest between stations, and 3 circuits/session in 21 minutes, and the 2nd protocol included 30 sec/set, 60 sec rest between sets, and 2 circuits/session. Both routines were performed in 21 minutes with 7 hydraulic machines (concentric resistance only: <a id="unilateral" data-tip="1551" target="_blank" href="/glossary-term/unilateral" class="glossary">unilateral</a> elbow flexion/extensions, bench press/horizontal rows, <a id="unilateral" data-tip="1551" target="_blank" href="/glossary-term/unilateral" class="glossary">unilateral</a> knee extension/flexions, shoulder press/lat pull downs, squats, pec fly/reverse flyes, seated leg abduction/adductions). The findings demonstrated that an average of 35% more reps were completed during the 30 sec rest between sets group; however, an average of 9% more reps/set were completed by the 60 sec rest between sets group. Additionally, the 30 sec rest between sets group exhibited higher average oxygen uptake, energy expenditure, and heart rate (141). This study demonstrates relationships between rest between exercises, reps/set, sets/session, and exercise volume during circuit training when session time is equal. Although more reps/set may be performed with longer rest between exercises (60 sec vs. 30 sec), these benefits should be compared to the potential for more sets performed during a session with a fixed length. Further, the studies mentioned above demonstrating similar outcomes between conventional and circuit protocols, compared resistance training with long (3 min) rest between set durations to circuit training with short (1 min) rest between exercises, which may suggest that longer than 1 minute rest between exercises is unnecessary.

Bibliography

&copy; 2022 Brent Brookbush
Questions, comments, and criticisms are welcomed and encouraged

Copyright

A-Band - Refers to the part of the muscle cell that looks darker under a microscope.  This area of the cell is darker due to parallel arrangement of thicker filaments (myosin) and overlap with the thinner filaments (actin).
<ul>
 	<li>As a muscle contracts, the A-band is where actin and myosin interact.</li>
</ul>
<ol>
 	<li>Saladin, K. (2014). Anatomy &amp; physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717</li>
</ol>

Accuracy - the proportion of individuals correctly identified by the test results.
<ul>
 	<li>For example, a special test with perfect accuracy would imply a test has 100% specificity, 100% sensitivity, 100% positive predictive value and 100% negative predictive values.</li>
</ul>

Action Potential - A rapid change in voltage, resulting in a wave of excitation, that may result in stimulation of a nerve or muscle cell.
<ul>
 	<li>In order for an action potential to be initiated, the resting membrane voltage must exceed the excitation threshold, which then results in a cascade of depolarization and the "wave of excitation." Any stimulus below that threshold will not result in an action potential, and a stimulus greater than the threshold will not increase a single action potential, but may result in additional action potentials.  In this way, the action potential functions more like an on/off switch (all or none), and less like a dimmer switch.</li>
</ul>

A single-joint movement pattern (most often) designed to load a specific under-active muscle(s), while minimizing the contribution of over-active synergists via specific cues/joint motions.
<ul>
 	<li style="text-align: left;">Activation techniques/exercises are performed with the intent of addressing a muscle exhibiting a reduction in activity (tone) as a result of, or contributing to postural dysfunction.</li>
 	<li style="text-align: left;">Activation techniques/exercises cannot be multi-joint movement patterns due to relative flexibility, altered reciprocal inhibition, and synergistic dominance resulting in compensation patterns.</li>
</ul>
Example, <a href="https://brentbrookbush.com/articles/corrective-exercise-articles/activation/gluteus-medius-activation-progression/" target="_blank">gluteus medius activation</a> involves resisted hip abduction while minimizing the contribution of the TFL via hip extension.

Active stretching is a term used to describe a stretch that involves an active contraction of opposing musculature to lengthen a muscle to its end range. Generally these stretches are held for 2-5 seconds and repeated for 8-15 repetitions.

Adenosine triphosphatase (ATPase): is the enzyme responsible for catalyzing (initiating and accelerating) the decomposition of ATP to ADP.
<ul>
 	<li>This dephosphorylation (breakdown) reaction releases energy for processes like muscular contraction.</li>
</ul>

Adenosine triphosphate (ATP): The molecule that functions as a universal energy-transfer molecule, providing most of the energy associated with muscular contraction and human movement. ATP is composed of an adenine group, a ribose group, and three molecules of inorganic phosphates.
<ul>
 	<li>Energy is provided when hydrolysis results in the cleaving of a phophate group; resulting in adenosine diphosphate, an inorganigic phosphate group, and energy.</li>
</ul>

Algometry - measuring the amount of pressure to result in sensitivity or pain, using an algometer.
<ul>
 	<li>Generally, research uses algometry to establish a minimum pain pressure threshold (PPT), in which a lower PPT implies more sensitivity and pain, and a higher PPT implies less sensitivity and pain. PPT is a common outcome measure in trigger point research.</li>
</ul>
<a href="https://brentbrookbush.com/wp-content/uploads/2019/07/Algometer.jpg"><img class="aligncenter wp-image-140177" src="https://brentbrookbush.com/wp-content/uploads/2019/07/Algometer.jpg" alt="Image of an Algometer" width="500" height="333" /></a>

All-or-none principle - a nerve or muscle cell's response to a stimulus is independent of the strength of the stimulus. If that stimulus exceeds the threshold potential (threshold of an action potential), the nerve or muscle fiber will respond completely; otherwise, there is no response.

Example, when a motor unit in the biceps brachii is stimulated it contracts the same way whether a 10 lb or 50 lb dumbbell is lifted.  It is actually the number of muscle cells and the size of the motor unit that determines force output.

&nbsp;

The transition period between eccentric load and concentric contraction during a repetition of an exercise.  This term is most often used in reference to power/plyometric exercises, in which a shorter amortization phase is believed to be beneficial.  The shorter amortization phase may better use the stored energy from the elastic deformation of connective tissue and enhance synchronization of myotatic (stretch) reflex with maximum voluntary contraction.

Example, the athlete was cued to spend as little time as possible in the bottom of their squat stance (the amortization phase) during a set of box jumps.

Muscles that oppose the prime mover and synergists for a given joint action.

That is, all the muscles that can perform the opposing joint action.

Example: The triceps and anconeus are antagonists during elbow flexion.

An anatomical direction; toward the front

Example, the face is on the anterior aspect of the head

Appendicular Skeleton - referring to the bones the bones of the arms and legs, as well as the bones that support them. This includes the pelvis, clavicle and scapula. There are approximately 126 bones in the appendicular skeleton.
<ul>
 	<li>Etymology - Appendicular, as in appendage, "that which is appended to something as a proper part," 1640s, from <a class="crossreference" href="https://www.etymonline.com/word/append?ref=etymonline_crossreference">append</a> + <a class="crossreference" href="https://www.etymonline.com/word/-age?ref=etymonline_crossreference">-age</a>. - <a href="https://www.etymonline.com/word/appendage" target="_blank" rel="noopener">Etymology Online</a></li>
</ul>
"Appendicular skeleton" is a label referring to a set of bones whose function is distinct from the bones of the "<a href="https://brentbrookbush.com/glossary/axial-skeleton/" target="_blank" rel="noopener">axial skeleton</a>".

A reflexive decrease in muscle activity due to joint dyskinesis.
For example, a reduction in deep cervical flexor activity as a result of cervical spine dyskinesis.

Arthrokinematic Motion - Small amplitude motions between bone surfaces at a joint.  The arthrokinematic motions are roll, glide (slide or translation), spin, compression and distraction (traction). Arthrokinematic motions accompany osteokinematic motions to maintain joint congruence.
<ul>
 	<li>Example, arthrokinematic motion of the talus includes posterior glide on the tibia during ankle dorsiflexion.</li>
</ul>
Synonyms include: arthrokinematics, passive accessory motion, joint play and component motion

&nbsp;

Assessment - is the act of assessing, i.e. determining the importance, size, or value of -

In most cases, the results of an assessment are compared to normative data. If the individual exhibits values that are within normal parameters, it may be assumed that the aspect of health or motion assessed is not contributing to the patient's complaint, symptoms or movement impairment. If the results fall outside of normal parameters, it may indicate that the aspect of health or motion assessed is contributing to, or being affected by the patient/client's complaint, symptoms, or movement impairment. In some cases, the results of an assessment are compared to an "ideal model." In this case, deviations from the ideal are noted as potential issues. For example, deviations noted in the <a title="Introduction to the Overhead Squat Assessment" href="https://brentbrookbush.com/online-courses/articles/assessment/introduction-overhead-squat-assessment/" target="_blank">Overhead Squat Assessment</a> are compared to an "ideal model" of posture and motion.

Assessments used by human movement professionals can be divided into three broad categories:
<ul>
 	<li>"Clear" the Patient/Client for Intervention - These are tests, assessments and evaluations used to determine if a patient/client's issue may improve given the assessing professional's scope, skills, abilities and willingness to treat that individual.
<ul>
 	<li>For example, many of the special tests used in orthopedic medicine assist in determining the level of pathology or likelihood of a particular diagnosis. Certain issues and diagnoses are beyond the scope of the human movement professional, and are better treated by diagnostic professionals in the medical community (physicians, podiatrists, surgeons, etc.). A Calf Squeeze (Thompson) Test is one example, in which a positive sign may indicate a rupture of the Achilles tendon that may be better treated via surgical intervention.</li>
</ul>
</li>
 	<li>Highlight Contraindications - Tests, assessments and evaluations used to stratify risk or preclude a professional from addressing certain tissues, motions or using a particular technique.
<ul>
 	<li>For example, the Vertebral Artery Test (VBI) is often used to determine if high velocity thrust mobilizations (manipulations) are safe for a patient with cervical dysfunction.</li>
</ul>
</li>
 	<li>Refine Exercise/Intervention Selection: Tests, assessments and evaluations used to assist the professional in determining which techniques, modalities and exercises will best address a patient/client's complaints or desired goals.
<ul>
 	<li>Most movement assessments fall into this category. For example, a positive <a href="https://brentbrookbush.com/vimeo_videos/elys-test-rectus-femoris-flexibility-assessment/" target="_blank">Ely's Test</a> may indicate a need to release and/or lengthen the <a href="https://brentbrookbush.com/articles/anatomy-articles/muscular-anatomy/rectus-femoris/" target="_blank">rectus femoris</a>.</li>
</ul>
</li>
</ul>
Note: An assessment, or assessment result, may fall into more than one category. For example, although goniometry is an assessment most often used to Refine Exercise/Intervention Selection, if a range of motion is significantly altered, with an abnormal end-feel, and/or causes the patient or client/pain, the individual may need to be referred to a physician for further testing and Clearance to resume rehab activities.  Further, that same patient may return to the human movement professional with a list of Contraindicated Activities from the physician. - "When in doubt, refer out!"

Axial Skeleton - referring to the bones of the head, neck, trunk and spinal column (does not include pelvis). There are approximately 80 bones in the axial skeleton.
<ul>
 	<li>Etymology - Axial, as in "axis", referring to "imaginary motionless straight line around which a body (such as the Earth) rotates," from Latin axis "axle, pivot, axis of the earth or sky" - <a href="https://www.etymonline.com/word/axis" target="_blank" rel="noopener">Etymology Online</a></li>
</ul>
"Axial skeleton" is a label referring to a set of bones whose function is distinct from the bones of the "<a href="https://brentbrookbush.com/glossary/appendicular-skeleton/" target="_blank" rel="noopener">appendicular skeleton</a>".

Balance - The ability to maintain a body’s center of mass over its base of support. Balance can be static or dynamic.
<ul>
 	<li>For example, maintaining balance is harder on one leg because the center of mass must stay over a much smaller base of support.</li>
</ul>

A ball and socket joint (also called a spheroid joint or spheroidal joint) is a synovial joint in which the rounded or spherical end of one bone fits into a cup-like depression of another bone. The distal bone is capable of motion around an indefinite number of axes, which have one common center. Examples include the hip and shoulder (glenohumeral joint)

Base of support (BoS) - refers to the area beneath an object or person, and the area within the perimeter created by every point of contact that the object or person makes with the supporting surface. This may include the <a href="https://brentbrookbush.com/articles/anatomy-articles/muscular-anatomy/gluteus-maximus/" target="_blank" rel="noopener">glutes</a> of someone sitting on a chair, or the back of someone leaning against a wall.
<ul>
 	<li>For example, during a single leg balance the BoS is the area of the foot in contact with the surface; however, when a person is standing on two feet, the BoS is the area of both feet and the surface between them.</li>
</ul>

Pertaining to both sides

Example, bilateral rows are performed with both arms at the same time.

Case-control Study - a particular form of retrospective study that samples a matched group of people who have, and do not have the outcome being studied. A case-control study is a quasi-experimental design, often used in medicine to aid in determining potential contributing factors (cannot determine causality). In this study type exposure is the dependent variable and outcome is independent.
<ul>
 	<li>Example, in this retrospective case-control, medical records were investigated for trends correlated with cervical pain (1).
<ol>
 	<li>Mäkela, M., Heliövaara, M., Sievers, K., Impivaara, O., Knekt, P., &amp; Aromaa, A. (1991). Prevalence, determinants, and consequences of chronic neck pain in Finland. American journal of epidemiology, 134(11), 1356-1367.</li>
</ol>
</li>
</ul>

An anatomical direction; toward the tail, relative to humans this term is often used to refer to "in the direction of the tale (toward the feet)".

Example, to release the trapezius muscle the therapist used a force directed caudally.

Center of mass (CoM) - an object's mean position of mass; that is, a point that is perfectly surrounded by an equal amount mass in all directions.

Center of gravity (CoG) - point where gravity appears to act. Since the human body is so small compared to the earth, we can assume gravity acts uniformly on the body, and that CoG and CoM are the same.
<ul>
 	<li>Example, the CoM of the human body while lying down or standing straight up is close to our navel. However, it is possible that during a resistance exercise, the combination of the body's weight and the weight of the resistance will place the combined CoM outside the body. For example, during the mid-portion of a <a href="https://brentbrookbush.com/vimeo_videos/back-squat/" target="_blank" rel="noopener">back squat</a> the CoM would be several anterior to the naval.</li>
</ul>

An anatomical direction; toward the head (synonym: cranial)

Example, hip pain was felt with any force directed cephalad.

Cohort Study - a particular form of longitudinal study that samples a cohort (a group of people who share a defining characteristic), performing a cross-section at intervals through-out a period of time. A cohort study is a quasi-experimental design often used in medicine to aid in determining etiology or a cause-and-effect relationship. In this study type exposure is the independent variable and outcome is dependent.
<ul>
 	<li>Example, the study by Cholewicki et al. (1) investigated Yale Varsity Athletes (the cohort) with 2 and 3 year follow up (longitudinal design) and found that trunk muscle response time to off-loading was predictive of future low back injury.</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/core/increased-trunk-muscle-latency-may-cause-rather-than-result-from-low-back-pain/" target="_blank" rel="noopener noreferrer">Cholewicki, J., Silfies, S., Shah, R., Greene, H., Reeves, N. Alvi, K., Goldberg, B. (2005). Delayed trunk muscle reflex responses increase the risk of low back injuries. Spine. 30(23), 2614-2620</a></li>
</ol>

Comparable Sign: A combination of pain, stiffness and/or spasm during examination that is comparable to the patients symptoms.
<ul>
 	<li>One common error made during evaluation with special tests is attention given to any discomfort or pain, rather than attempting to identify the pain/discomfort related to the patient's complaint (concordant/comparable sign). Many special tests purposefully test tissue limits and are at least mildly uncomfortable in every individual. Basing your assessment on positive tests that resulted in "concordant/comparable signs" will improve your chances of arriving at the correct diagnosis.</li>
</ul>

An alternative movement pattern that has been adopted to compensate for dysfunction/impairment in the human movement system.
Example: A lack of calf extensibility may limit dorsiflexion, leading to the knees bowing inward (functional valgus) and excessive forward lean of the torso during a squat.

An arthrokinematic motion - the approximation of joint surfaces; that is, a force that directs one bone surface into another resulting in a reduction in intra-articular volume. Although widely thought of as a "destructive force", it is likely best to consider compression as a naturally occurring, stabilizing force. Any arthrokinematic force in excess (spin, glide, roll, traction) may be viewed as potentially deleterious.

For example, during a squat the femoral head is compressed into the acetabulum by muscular forces, bodyweight and any additional external load.

Concave (Concavity) - Having an outline or surface curved like the interior surface of a bowl or sphere - to cave-in or curve inward.
<ul>
 	<li>Example, the internal surfaces of the pelvis is concave, holding some of the bodies viscera.</li>
</ul>

Concordant Sign - The patient's specific pain, symptom or complaint. 
<ul>
 	<li>One common error made during evaluation with special tests is attention given to any discomfort or pain, rather than attempting to identify the pain/discomfort related to the patient's complaint (concordant/comparable sign). Many special tests purposefully test tissue limits and are at least mildly uncomfortable in every individual. Basing your assessment on positive tests that resulted in "concordant/comparable signs" will improve your chances of arriving at the correct diagnosis.</li>
</ul>

Conductivity: Stimulation results in more than a local effect (1).
<ul>
 	<li>For example, in a muscle cell the stimulation of a motor endplate results in a change in cell membrane polarity that rapidly propagates (is conducted) along the entire length of the muscle cell, stimulating all sacromere.</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

A condyloid joint (also called condylar, bicondylar, ellipsoid, or ellipsoidal) is an ovoid articular surface, or condyle, that is received into an elliptical cavity.  These joints permit movement in two planes.  Examples include the knee, metacarpophalangeal joints and metatarsophalangeal joints.

Connective Tissue Cell - One of the four basic types of animal tissue, consisting mostly fibers and ground substance.  These cells are specialized to binds organs together, holds them in place, protect them from external forces, and may fill space in the body's cavities.

Example, the body's muscles are enclosed in durable connective tissue sheets known as the "epimysium", "perimysium", and "endomysium," which and in support and transmitting force.
<ol>
 	<li>Saladin, K. (2014). Anatomy &amp; physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717</li>
</ol>

Contractility: The ability to shorten (1).
<ul>
 	<li>Contractility: Muscle cells are unique in the amount they can shorten when stimulated; this is this largerly due to the highly organized and unique arrangement of myofilaments (actin and myosin).</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

Pertaining to the opposite side

Example, the external oblique muscle performs contralateral rotation; rotation to the opposite side.

Convex (Convexity) - Having an outline or surface curved like the exterior of a circle or sphere - to bulge or curve outward.
<ul>
 	<li>Example, the top of your head is shaped by the convex exterior surface of your skull.</li>
</ul>

Correlational Research - Non-experimental <a href="https://www.questionpro.com/blog/what-is-research/">research</a> method in which the statistical relationship between two variables is investigated.
<ul>
 	<li>In this research by Kwon et al., a correlation was noted between a decrease in extensibility during a hamstring length test (goniometry) and current knee pain (1).</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/knee/correlation-patellofemoral-pain-syndrome-pfps-hamstring-activity/" target="_blank" rel="noopener">Kwon O, Yun M, and Lee W. (2014). Correlation between intrinsic patellofemoral pain syndrome in young adults and lower extremity biomechanics. J. Phys. Ther. Sci. 26: 961-964</a></li>
</ol>

Counter-nutation - posterior rotation of sacrum relative to ilium, and/or anterior rotation of ilium relative to sacrum.
<ul>
 	<li>The pelvic floor muscles are examples of muscle that may counter-nutate the sacrum.</li>
</ul>
[caption id="attachment_126335" align="aligncenter" width="400"]<a href="https://brentbrookbush.com/wp-content/uploads/2018/10/Nutation.png"><img class=" wp-image-126335" src="https://brentbrookbush.com/wp-content/uploads/2018/10/Nutation.png" alt="Nutation and Counter-nutation of the Sacroiliac Joint" width="400" height="967" /></a> Nutation and Counter-nutation of the Sacroiliac Joint[/caption]

&nbsp;

Crossover (Study) Design - A type of longitudinal, repeated measures quasi-experimental design in which each group receives both treatments, but at different times. It is named "crossover" due to the patients "crossing-over" to the other treatment or sham group after a specified period of time.
<ul>
 	<li>This type of study has the advantage of every individual serving as their own control, which may reduce the influence of confounding variables.</li>
 	<li>Unfortunately, the design itself introduces the chances that anyone receiving the experimental variable in the first period will continue to be effected in the second period.</li>
</ul>
In a study by Senna et al., a cross-over design was used to investigate the difference load made on inter-set rest intervals (1).
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/strength-training-research-corner/heavy-vs-light-load-single-joint-exercise-performance-with-different-rest-periods/" target="_blank" rel="noopener">Senna, G.W., Rodrigues, B.M., Sandy, Scudese, Bianco, A, &amp; Dantas, E.H.M. (2017). Heavy vs light load single-joint exercise performance with different intervals. Journal of Human Kinetics, 58, 197-206. </a></li>
</ol>

Cross-sectional Study - a research design that involves gathering data from a population or representative subset at a specific point in time.
<ul>
 	<li>Example, the study by Karimi-Mobarake et al.(1) investigated the prevalence of genu varum and genu valgum among school children 7-11 years old in Iran.</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/knee/low-prevalence-of-genu-varum-and-valgum-among-elementary-school-children/" target="_blank" rel="noopener noreferrer">Karimi-Mobarake, M., Kashefipour, A., Yousfnejad, Z. The prevalence of genu varum and genu valgum in primary school children in Iran 2003-2004. (2005) Journal of Medical Science 5(1). 52-54</a></li>
</ol>

Cytokine - A broad and loose category of small proteins that act through receptors, and are especially important to immune function (inflammation).
<ul>
 	<li>Cytokines include substances such as interferon, interleukin, and growth factors, which are secreted by certain cells of the immune system and have an effect on other cells. Their definite distinction from hormones is a topic of continued research.</li>
</ul>
&nbsp;

Dependent variable - in research, this is the variable that is changed by the independent variable, most often this is the "outcome" of the study.
<ul>
 	<li>Example, in the study by Cleland et al. (1), the independent variable is "thoracic manipulation," and the dependent variable is "lower trapezius muscle strength."</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/short-term-effects-lower-thoracic-manipulation-lower-trapezius-muscle-strength/" target="_blank" rel="noopener noreferrer">Cleland J, Selleck B, Stowell T, Brown L, Alberini S, St. Cyr H, Caron T. Short-term Effects of Thoracic Manipulation on Lower Trapezius Muscle Strength.  Journal of Manual &amp; Manipulative Therapy. 2004; 12(2): 82-90</a></li>
</ol>

An anatomical direction; further from the trunk or center of the body

Example, the foot is at the distal end of the leg.

An arthrokinematic motion - a force applied to a body part that may result in the separation of joint surfaces, a reduction in intra-articular pressure, and/or an increase in intra-articlar space.

For example, to hang from one's hands (i.g. in preparation for a pull-up) results in a traction force on the glenohumeral joint (shoulder).

An anatomical term of location; back or upper surface

Example, shoe laces may compress tissues on the dorsal surface of the foot

The "drawing-in" maneuver is a common cue used during exercise and rehabilitation programs. A light contraction of the <a href="https://brentbrookbush.com/articles/muscular-anatomy/transverse-abdominis/" target="_blank" rel="noopener">transverse abominis</a> (and potentially the entire <a href="https://brentbrookbush.com/articles/corrective-exercise-articles/core-subsystems/intrinsic-stabilization-subsystem/" target="_blank" rel="noopener">intrinsic stabilization subsystem</a>) achieved by gently pulling the lower abdominal region away from one's waist band. This should have minimal effect on breathing, and should not be confused with a maximal contraction of the <a href="https://brentbrookbush.com/articles/muscular-anatomy/transverse-abdominis/" target="_blank" rel="noopener">transverse abdominis</a> resulting in a "vacuum pose".
<ul>
 	<li>Research often refers to this maneuver as the "abdominal drawing-in maneuver"; abbreviated ADIM.</li>
</ul>
Development and introduction of this cue into practice is based on the pivotal research and resulting text:
<ol>
 	<li>Carolyn Richardson, Paul Hodges, Julie Hides. Therapeutic Exercise for Lumbo Pelvic Stabilization – A Motor Control Approach for the Treatment and Prevention of Low Back Pain: 2nd Edition (c) Elsevier Limited, 2004</li>
</ol>

Faulty or abnormal movement; an alteration of normal kinematics.

For example, joint stiffness or a reduction in arthrokinematics motion that results in limited osteokinematic range of motion - inadequate inferior glide of the femoral head resulting in limited abduction of the hip.

The seeping into, or abnormal collection of fluid in a body cavity.

For example, knee effusion describes swelling within the knee joint.

Note: the word "effusion" is used differently in medicine than it is used in reference to the movement (seeping out) of liquids and gases, for example in chemistry.

&nbsp;

A trait of body tissues that allows a tissue to return to its resting length or state after deformation or stretch.
Example:  Muscle is elastic tissue; many muscles will return to their resting length after being stretched to 150% of that length without any appreciable change in tissue quality.

Elasticity: Elasticity refers to the ability of a cell to return to its resting length after being stretched/lengthened.
<ul>
 	<li>Note: this term is often confused with extensibility. Elasticity is not the ability to stretch; it is the ability to return to normal length after being stretched. Muscle tissue, connective tissue and even nerve tissue have varying levels of elasticity.</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

Epithelial cell - One of the four basic cell types, found lining the body's cavities, blood vessels, organs and constitutes most gland tissue.  These cells are specialized to aid with absorption, secretion, or act as a barrier from foreign objects.
<ol>
 	<li>Saladin, K. S., &amp; Miller, L. (1998). Anatomy &amp; physiology. New York (NY): WCB/McGraw-Hill.</li>
</ol>

Equilibrium - a state in which opposing forces or influences are balanced.
<ul>
 	<li>For example, to maintain a neutral trunk while pushing or pulling a weight in one hand, your core musculature must balance the force by creating an equal amount of force in the opposite direction.</li>
</ul>

The study of causation, or origination. The word is commonly used in the medical professions, where it may refer to the study of why things occur, or the reason behind why things act a certain way.

For example, the etiology of low back pain is a complex subject, with multiple contributing factors and various structures implicated.

<div class="gs_citr" tabindex="0">Evidence-based medicine (practice) is the integration of best research evidence with clinical expertise and patient(client) values (2)."</div>
<ul>
 	<li class="gs_citr" tabindex="0">...the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients (clients).  It involves the integration of at least (a) clinical expertise/expert opinion, (b) external scientific evidence, and (c) client/patient/caregiver perspectives to provide high-quality services reflecting the interests, values, needs, and choices of the individuals we serve (1).</li>
</ul>
&nbsp;
<ol>
 	<li id="gs_cit1" class="gs_citr" tabindex="0">Sackett, D. L., Rosenberg, W. M., Gray, J. M., Haynes, R. B., &amp; Richardson, W. S. (1996). Evidence based medicine: what it is and what it isn't. Bmj, 312(7023), 71-72.</li>
 	<li class="gs_citr" tabindex="0">Sackett D et al. Evidence-Based Medicine: How to Practice and Teach EBM, 2nd edition. Churchill Livingstone, Edinburgh, 2000, p.1</li>
</ol>

Excitability: The ability of a cell to change in membrane conductance as a response to stimulation.

<ul>
 	<li>For example, muscle cells are specialized to react to a change in membrane potential with contraction, where as nerve cells are specialized to propagate a change in membrane potential along there axons and communicate that message to other tissues via neurotransmitters.
</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

Excitation threshold: The level that a depolarization must reach for an action potential to occur.
<ul>
 	<li>The excitation threshold is a contributing factor to the "all-or-none" response of muscle and nerves cells to a stimulus.</li>
</ul>

Exercise Progression - Modification of an exercise with the intent of promoting adaptation by increasing demand. This can be accomplished by increasing reps, load, tempo, range of motion, complexity, and/or challenge to an individual's stability.
<ul>
 	<li>Because load, reps, tempo and complexity are often explicitly noted, the term "exercise progression" is most often used throughout Brookbush Institute (BI) content to refer to an exercise, or series of exercises that make it harder to maintain stability with good form.
<ul>
 	<li>Sample Exercise Progression: <a href="https://brentbrookbush.com/vimeo_videos/kneeling-chop-pattern/" target="_blank" rel="noopener">Kneeling Chop</a> to <a href="https://brentbrookbush.com/vimeo_videos/static-standing-chop-pattern/" target="_blank" rel="noopener">Standing Chop</a> to <a href="https://brentbrookbush.com/vimeo_videos/single-leg-chop-pattern/" target="_blank" rel="noopener">Single-leg Chop</a></li>
</ul>
</li>
</ul>

Exercise regression - The opposite of progression; that is, modification of an exercise with the intent of reducing demand. This can be accomplished by decreasing reps, load, tempo, range of motion, complexity, and/or challenge to an individual's stability. Generally, regressions are used to modify an exercise to the client's current level of ability, with the intent of improving form, motor learning and retention.
<ul>
 	<li>Because load, reps, tempo and complexity are often explicitly noted, the term "exercise regression" is most often used throughout Brookbush Institute (BI) content to refer to an exercise or series of exercises that make it easier to maintain stability with good form.
<ul>
 	<li>Sample Exercise Regression: <a href="https://brentbrookbush.com/vimeo_videos/single-leg-chop-pattern/" target="_blank" rel="noopener">Single-leg Chop</a> to <a href="https://brentbrookbush.com/vimeo_videos/static-standing-chop-pattern/" target="_blank" rel="noopener">Standing Chop</a> to <a href="https://brentbrookbush.com/vimeo_videos/kneeling-chop-pattern/" target="_blank" rel="noopener">Kneeling Chop</a></li>
</ul>
</li>
</ul>

Experimental Research - Studies in which the researchers introduce the variable to be studied, with the intent of observing the outcome. This is different than observational research which observes the effect of a variable already present. Many texts also assert that experimental research should include randomization and ideally a control group, as is seen in Randomized Control Trials. Studies in which the variable is introduced by the researchers, but participants are not randomized may be considered Quasi-experimental research.
<ul>
 	<li>In this study by Esformes, the experimental variable was squat depth and the outcome measures observed were various performance measures related to power (1).</li>
</ul>
<ol>
 	<li><a href="https://brookbushinstitute.com/article/back-squat-depth-lower-body-post-activation-potentiation/" target="_blank" rel="noopener">Esformes, J., &amp; Bampouras, T. (2013). Effect of back squat depth on lower-body postactivation potentiation. Journal of Strength and Conditioning Research, 27(11), 2997-3000.</a></li>
</ol>
&nbsp;

Extensibility: The ability of a cell to be stretched or lengthened without damage (1).
<ul>
 	<li>For example, most cells would rupture with even a modest stretch, but muscles can stretch up to 3 times their contracted length.</li>
</ul>
<ol>
 	<li>Saladin, K. (2012). Anatomy &amp; Physiology: The unity of form and function. (6th ed.). New York: McGraw-Hill.</li>
</ol>

False Negative - the proportion of negatives in a group that were assessed incorrectly (assessed as negative when the patient was actually positive)
<ul>
 	<li>Test Results: Although most tests/assessments result in either a positive or negative, the accuracy of a test is dependent on the number  of positives and negatives that are correct. Therefore, when the accuracy of a test is determined, their are 4 possible results, because a positive or negative result could be right (true) or wrong (false).</li>
</ul>

False Positive - the proportion of positives in a group that were assessed incorrectly (assessed as positive when the patient was actually negative)
<ul>
 	<li>Test Results: Although most tests/assessments result in either a positive or negative, the accuracy of a test is dependent on the number  of positives and negatives that are correct. Therefore, when the accuracy of a test is determined, their are 4 possible results, because a positive or negative result could be right (true) or wrong (false).</li>
</ul>

The function of fascia is to transmit force, provide support, and protect tissues. Fascia can effect motion by:
Transmitting force from one or more muscles (example: the thoracolumbar fascia)
Restricting motion in cases of adaptive shortening and/or adhesion to proximal structures (example: iliotibial band in cases of lower-leg dysfunction)
Elastic recoil after stretching can contribute to force production (example: plyometric exercise)

Note: There is evidence that fascia may house more receptors related to human movement than other tissues. In this way fascia may act as a motherboard for the nervous system

The fascial system does not contract or develop trigger points, and its capacity to adapt to stretching and or strengthening exercise is limited, especially when compared to the adaptive capacity of muscle tissue.

Fibromyalgia - A loosely defined diagnosis that is associated with a combination of widespread pain in combination with 2) tenderness at 11 or more of the 18 specific tender point sites. Consideration may also be given to the presence of psychosocial stressors and inflammatory disease in the patients history. Newer research suggests that fibromyalgia may be at least in part due to central sensitization of myofascial pain, often associated with trigger points (1 - 4).
<ol>
 	<li>Wolfe, F. (2018). Fibromyalgia Syndrome and Fibromyalgia Syndrome Criteria: Problems in Definition and Validity. Fibromyalgia Syndrome and Widespread Pain: From Construction to Relevant Recognition.</li>
 	<li>Wolfe, F., Smythe, H. A., Yunus, M. B., Bennett, R. M., Bombardier, C., Goldenberg, D. L., ... &amp; Fam, A. G. (1990). The American College of Rheumatology 1990 criteria for the classification of fibromyalgia. Arthritis &amp; Rheumatism: Official Journal of the American College of Rheumatology, 33(2), 160-172.</li>
 	<li>Alonso-Blanco, C., Fernandez-de-las-Penas, C., Morales-Cabezas, M., Zarco-Moreno, P., Ge, H. Y., &amp; Florez-García, M. (2011). Multiple active myofascial trigger points reproduce the overall spontaneous pain pattern in women with fibromyalgia and are related to widespread mechanical hypersensitivity. The Clinical journal of pain, 27(5), 405-413.</li>
 	<li>Staud, R., Nagel, S., Robinson, M. E., &amp; Price, D. D. (2009). Enhanced central pain processing of fibromyalgia patients is maintained by muscle afferent input: a randomized, double-blind, placebo-controlled study. PAIN®, 145(1-2), 96-104.</li>
</ol>
&nbsp;

Muscles that act to reduce or prevent movement at proximal joints to improve force transmission.
Example: The muscles of the core are important fixators; reducing motion of the spine/trunk to enhance force transmission between the extremities and environment.

An increase in joint stability via compressive forces resulting from muscular contraction and increased tension in fascial structures (1,2).
<ul>
 	<li>This term is most often used in reference to core intrinsic stabilizers, the thoracolumbar fascia and the sacroiliac joint; however, force closure and form closure have been mentioned in the literature referring to other joints.</li>
 	<li>Related term: Form closure</li>
</ul>
<ol>
 	<li>Andry Vleeming, Vert Mooney, Rob Stoeckart. Movement, Stability &amp; Lumbopelvic Pain: <a class="glossaryLink " title="Glossary: Integration" href="https://brentbrookbush.com/glossary/integration/" target="_blank" rel="noopener noreferrer" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Integration&lt;/div&gt;&lt;div class=glossaryItemBody&gt;Making a whole of parts.&lt;br /&gt;&lt;br /&gt;Example, The Brookbush Institute uses an integrative approach to explaining and addressing human movement.&lt;/div&gt;">Integration</a> of Research and Therapy. (c) 2007 Elsevier Limited</li>
 	<li id="gs_cit1" class="gs_citr" tabindex="0">Vleeming, A., Pool-Goudzwaard, A. L., Stoeckart, R., van Wingerden, J. P., &amp; Snijders, C. J. (1995). The Posterior Layer of the Thoracolumbar Fascia| Its Function in Load Transfer From Spine to Legs. Spine, 20(7), 753-758.</li>
</ol>

The relative contribution of joint shape and structure to the stability of a joint (1,2).
<ul>
 	<li>This term is most often used in reference to the "rough" articulating surfaces of the sacroiliac joint and the wedge shape of the sacrum; however, force closure and form closure have been mentioned in the literature referring to other joints.</li>
 	<li>Related term: Force closure</li>
</ul>
<ol>
 	<li>Andry Vleeming, Vert Mooney, Rob Stoeckart. Movement, Stability &amp; Lumbopelvic Pain: <a class="glossaryLink " title="Glossary: Integration" href="https://brentbrookbush.com/glossary/integration/" target="_blank" rel="noopener noreferrer" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Integration&lt;/div&gt;&lt;div class=glossaryItemBody&gt;Making a whole of parts.&lt;br /&gt;&lt;br /&gt;Example, The Brookbush Institute uses an integrative approach to explaining and addressing human movement.&lt;/div&gt;">Integration</a> of Research and Therapy. (c) 2007 Elsevier Limited</li>
 	<li id="gs_cit1" class="gs_citr" tabindex="0">Vleeming, A., Pool-Goudzwaard, A. L., Stoeckart, R., van Wingerden, J. P., &amp; Snijders, C. J. (1995). The Posterior Layer of the Thoracolumbar Fascia| Its Function in Load Transfer From Spine to Legs. Spine, 20(7), 753-758.</li>
</ol>

An arthrokinematic motion - linear motion across a joint surface parallel to the plane of the adjacent joint surface, just as your posterior moves relative to a "slide" in a park.

For example, the glide of facet joint in the spine during spinal flexion and extension, or the posterior glide of the humeral head that must accompany anterior roll to maintain congruence with glenoid fossa during shoulder horizontal adduction.

A plane joint (also called an arthrodial joint, gliding joint or plane articulation) is a synovial joint which allows only gliding movement in the plane of the articular surfaces. The opposed surfaces of the bones are flat or almost flat, with movement generally limited by tight capsules and ligaments. Plane joints are numerous, are most often small, and allow very little motion.  Examples include the carpal joints of the wrist, the tarsal joints of the ankle, and the facet joints of the spine.

"...refers to the measurement of angles, in particular the measurement of angles created at human joints by the bones of the body (1).

&nbsp;
<ol>
 	<li>Cynthia C. Norkin, D. Joyce White. Measurement of Joint Motion: A Guide to Goniometry 3rd Edition. Copyright (C) 2003 by F.A. Davis Company</li>
</ol>

Ground reaction force (GRF) - The force exerted by the ground on the body in contact with it.

For example, when a runner's foot strikes the ground with a force equal to the mass of the individual times their acceleration due to gravity, momentum and muscular exertion, the ground exerts an equal and opposite force on the runner's foot.
<ul>
 	<li>GRF is often measured in research studies using force plates as a means of quantitatively measuring the force generated by an individual.</li>
</ul>

H-Band - Refers to the central zone of a sarcomere that looks lighter under a microscope.  This area of the sarcomere is a lighter portion of the A-band where there is no overlap between the thinner filaments (actin), and the thicker filaments (myosin).
<ul>
 	<li>Example, when a muscle contracts, actin and myosin cross-bridging occurs in the region of the A-band until the H-band is reached where no overlap occurs.</li>
</ul>
<ol>
 	<li>Saladin, K. (2014). Anatomy &amp; physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717</li>
</ol>

A hinge joint (also called a ginglymus) is a synovial joint in which the articular surfaces fit one another in a way that only permits motion in one plane. Examples include the elbow, the knee (unless considered a condyloid joint) and the interphalangeal joints.

Holism (holistic) (biological holism) - (from Greek holos "all, whole, entire") is the idea that systems and their properties should be viewed as wholes, not just as a collection of parts.
<ul>
 	<li>Summarized by Aristotle in his "Metaphysics": "The whole is more than the sum of its parts". However, the term "holism" was introduced into language by the South African statesman Jan Smuts as recently as 1926. (Smuts J. C. 1987 [1926]. Holism and evolution. Cape Town: N &amp; S Press.)</li>
</ul>
Example: The Brookbush Institute promotes a holistic approach to human movement science, in which the muscular, fascial, articular and neural systems are not viewed as separable and all proximal segments are considered.

Hormone: Chemical messengers produced by the endocrine system, transported via tissue fluids such as blood, to stimulate cells to "act."
<ul>
 	<li>Example: Growth hormone is secreted by the pituitary gland in the brain; stimulating growth, cell reproduction and cell regeneration in certain types of cells</li>
</ul>
The English physician E. H. Starling discovered in collaboration with the physiologist W. M. Bayliss secretin, the first hormone, in 1902. (1).
<ol>
 	<li>Henriksen, J. H., &amp; de Muckadell, O. S. (2000). Secretin, its discovery, and the introduction of the hormone concept. Scandinavian journal of clinical and laboratory investigation, 60(6), 463-472.</li>
</ol>

A range of motion achieved by the patient/client that is more than normal.
<ul>
 	<li>Note: Both hyper-mobility and hypo-mobility may adversely affect motion and may lead to deleterious effects on joints and soft tissue over time. There is no evidence to suggest that more or less flexibility than normal is beneficial.</li>
</ul>
Example: If an individual can place their forehead on their knees they are likely hypermobile at one, if not several joints

Example 2: 110° of shoulder external rotation would be considered hyper-mobile.

Hyperplasia is an increase in organic tissue size due to an adaptive increase in the number of cells per organ.
<ul>
 	<li>Although muscle hyperplasia has been noted in some animals, human muscle tissue does not seem to have this adaptive ability.</li>
</ul>

A condition of excessive tone of the skeletal muscles; increased resistance of muscle to passive stretching.  May be related to increased neural drive, synergistic dominance, trigger points, reflexive over-activity, and/or muscle length.
Example:  Individuals who exhibit ankle eversion and abduction during an overhead squat assessment likely have hypertonic fibularis (peroneal) muscles.

Muscular hypertrophy is an increase in muscle mass/size due to increase in the volume and cross-sectional area (CSA) of individual muscle cells. The increase in cross-sectional area can be attributed to an an increase in contractile proteins and structural elements (myofibrillar hypertophy), as well as an increase in glycogen storage and elements related to metabolism (sarcoplasmic hypertophy). Hypertrophy is an adaptation of both cardiac and skeletal muscle fibers in response to progressive increases in workload.
<ul>
 	<li>Note: Hypertrophy is not hyperplasia. Hyperplasia is an increase in muscle size due to an adaptive increase in the number of muscle fibers/cells per muscle. This type of adaptation does not occur in human muscle tissue.</li>
</ul>

A range of motion achieved by a patient/client that is less than normal.
<ul>
 	<li>Note: Both hyper-mobility and hypo-mobility may adversely affect motion and may lead to deleterious effects on joints and soft tissue over time. There is no evidence to suggest that more or less flexibility than normal is beneficial.</li>
</ul>
Example: If the end range of shoulder external rotation is reached and measured as 75° during goniometric assessment, the client/patient is exhibiting hypomobility of the glenohumeral joint (shoulder).

Hypothesis - a proposed explanation for a phenomenon; "scientific hypotheses" are generally constructed in a way that is testable or falsifiable.
<ul>
 	<li>Example: The hypothesis, "excessive knee valgus may be correlated with future knee pain and injury," has been the subject of several studies published over the last decade.</li>
</ul>

Diminished tone of skeletal muscles; diminished resistance of muscles to passive stretching.   May be related to inhibition, reciprocal inhibition, arthrokinematics inhibition and/or  increased resting length of muscle.
Example:  If your knees cave (hip adduction) during a squat or leg-press it is likely that your gluteus medius is hypotonic.

I-Band - Refers to the part of the muscle cell that looks lighter under a microscope.  This area of the cell is lighter due to parallel arrangement of thinner filaments (actin), and no overlap with the thicker filaments (myosin).
<ul>
 	<li>As a muscle contracts, the I-bands will decrease in width and move closer to one another.</li>
</ul>
<ol>
 	<li>Saladin, K. (2014). Anatomy &amp; physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717</li>
</ol>

Independent variable - in research, this is the variable or phenomenon being manipulated in the study.
<ul>
 	<li>Example, in the study by Ghanbari et al. (1), the independent variable is "knee joint mobilization", the dependent variable is "quadriceps muscle strength."</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/effect-knee-joint-mobilization-quadriceps-muscle-strength/" target="_blank" rel="noopener noreferrer">Ghanbari A. and Kamalgharibi S. (2013). Effect of knee joint mobilization on quadriceps muscle strength. International Journal of Health and Rehabilitation Sciences. 2(4): 186-191</a></li>
</ol>

An anatomical direction; toward the bottom (below)

Example, the mouth is inferior to the eyes

A reduction in neural drive, muscular activity, and or force output due to altered neuromuscular reflex.  Alterations in neuromuscular reflex may occur due to increases in muscle length (hypothesis: increased excitation threshold), altered reciprocal inhibition in response to increased antagonist tone, and or alterations in joint motion (arthrokinematics inhibition).

Making a whole of parts.

Example, The Brookbush Institute uses an integrative approach to explaining and addressing human movement.

Intermuscular Coordination - Optimal timing and motor unit recruitment of agonists, antagonists, synergists, neutralizers, stabilizers and fixators.

Example: Role of Muscles during Hip Extension
<ul>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Prime Mover" href="https://brentbrookbush.com/glossary/prime-mover/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Prime Mover&lt;/div&gt;The muscle most responsible for a joint action under load -&lt;br /&gt;&lt;br /&gt;That is, the muscle that can produce the most force for a given joint action. Often this term is used synonymously with the term agonist. The prime mover as defined above, may or may not be the most active muscle for a joint action during activities of daily living.&lt;br /&gt;&lt;br /&gt;Example: the gluteus maximus is the most powerful hip extensor and therefore the prime mover; however, the hamstrings are likely the most active hip extensors during low level activities like walking or standing.">Prime Mover</a>:  <a href="https://player.vimeo.com/external/82855344.hd.mp4?s=54c3e7d98fb9d4e0af8d282c85ba9b3e">Gluteus maximus</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Synergists" href="https://brentbrookbush.com/glossary/synergists/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Synergists&lt;/div&gt;Muscles that assist the prime mover in performing a joint action.&lt;br /&gt;&lt;br /&gt;That is, all muscles that can perform a joint action that are not the prime mover, are termed synergists.&lt;br /&gt;Example: The rectus abdominis is the prime mover of spinal flexion. All other muscles that can perform spinal flexion are synergists including – external obliques, internal obliques and psoas.">Synergists</a>: <a href="https://brentbrookbush.com/articles/muscular-anatomy/biceps-femoris/">Biceps femoris (long head)</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/semitendinosus-and-semimembranosus/">semitendinosus, semimembranosus</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/adductors/">posterior head of adductor magnus</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Antagonist" href="https://brentbrookbush.com/glossary/antagonists/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Antagonist&lt;/div&gt;Muscles that oppose the prime mover and synergists for a given joint action.&lt;br /&gt;&lt;br /&gt;That is, all the muscles that can perform the opposing joint action.&lt;br /&gt;&lt;br /&gt;Example: The triceps and anconeus are antagonists during elbow flexion.">Antagonists</a>: <a href="https://brentbrookbush.com/articles/muscular-anatomy/psoas/">Psoas</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/iliacus/">iliacus</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/tensor-fascia-latae-tfl/">tensor fascia latae</a> (TFL),<a href="https://brentbrookbush.com/articles/muscular-anatomy/rectus-femoris/"> rectus femoris</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/adductors/">anterior adductors (especially pectineus)</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/sartorius/">sartorius</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Neutralizer" href="https://brentbrookbush.com/glossary/neutralizers/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Neutralizer&lt;/div&gt;Muscles that oppose unwanted joint motions created by the prime mover and/or synergists, and/or muscles that prevent unwanted ancillary motion.&lt;br /&gt;Example: The teres minor and infraspinatus neutralize the internal rotation force created by the pectoralis major during horizontal adduction of the shoulder.">Neutralizers</a>: <a href="https://brentbrookbush.com/articles/muscular-anatomy/gluteus-minimus/">Gluteus minimus</a> and <a href="https://brentbrookbush.com/articles/muscular-anatomy/gluteus-medius/">anterior fibers of gluteus medius</a> neutralize external rotation force of <a href="https://brentbrookbush.com/articles/muscular-anatomy/gluteus-maximus/">gluteus maximus</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Stabilizer" href="https://brentbrookbush.com/glossary/stabilizers/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Stabilizer&lt;/div&gt;Muscles whose primary role is to improve arthrokinematics by maintaining optimal alignment of joint surfaces.&lt;br /&gt;&lt;br /&gt;Most often these muscles are the most intrinsic muscles of a joint, have a larger percentage of Type I muscle fibers and are rich in proprioceptors.&lt;br /&gt;Example: The muscles of the rotator cuff act as stabilizers for most shoulder motions.">Stabilizers</a>: <a href="https://brentbrookbush.com/articles/muscular-anatomy/deep-rotators-of-the-hip/">Deep rotators of hip</a></li>
 	<li><a class="glossaryLink " style="box-sizing: border-box; font-family: roboto; color: #000000 !important; font-size: 15px; outline: none; background: transparent; border-bottom: 1px dotted #000000 !important; text-decoration: none;" title="Glossary: Fixator" href="https://brentbrookbush.com/glossary/fixators/" target="_blank" rel="noopener" data-cmtooltip="&lt;div class=glossaryItemTitle&gt;Fixator&lt;/div&gt;Muscles that act to reduce or prevent movement at proximal joints to improve force transmission.&lt;br /&gt;Example: The muscles of the core are important fixators; reducing motion of the spine/trunk to enhance force transmission between the extremities and environment.">Fixators</a>: <a href="https://brentbrookbush.com/articles/core-subsystems/intrinsic-stabilization-subsystem/">Intrinsic stabilization subsystem</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/rectus-abdominis/">rectus abdominis</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/internal-obliques/">internal</a> and <a href="https://brentbrookbush.com/articles/muscular-anatomy/external-obliques/">external obliques</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/quadratus-lumborum/">quadratus lumborum</a>, <a href="https://brentbrookbush.com/articles/muscular-anatomy/erector-spinae/">erector spinae</a></li>
</ul>
&nbsp;

Example from: <a href="https://brentbrookbush.com/articles/anatomy-articles/introduction-to-functional-anatomy/kinesiology-of-the-hip/" target="_blank" rel="noopener">Introduction to Functional Anatomy: Kinesiology of the Hip</a>

Intramuscular coordination refers to the coordinated recruitment of motor units within a single muscle. This concept is used to explain increases in maximal strength and power; however, the coordinated and sequential recruitment of motor units is also essential to strength endurance and smooth coordinated motion.  Related terminology may include; motor unit recruitment, preferential recruitment, rate coding, sequence, etc..

Example: It is hypothesized that the "shaking" noted during a novice exercisers attempt at an activity like the <a href="https://brentbrookbush.com/vimeo_videos/ball-crunch-and-progressions/" target="_blank">stability ball crunch</a> may be due to relatively poor intramuscular coordination. Rather than smooth, sequential firing of rectus abdominis motor units, groups of motor units turn on and off in an uncoordinated manner.

Pertaining to the same side

Example, the quadratus lumborum performs ipsilateral flexion; lateral flexion toward the same side as the muscle.

An isoform, or variant, is a member of a set of similar proteins, that originate from the same gene, or gene family.
<ul>
 	<li>Example, the variations in myosin heavy chain proteins (MHC I, MHC IIA, MHC IIB/X) that contribute to the characteristic differences between muscle fiber types.</li>
</ul>

“The Prime Assumption”
Everything crossing a joint will influence joint motion during every joint action.

A concept that has expanded over the past several decades to describe the integration of 4 body systems (muscle, joints, fascia and nerves), as well as, the coordinated function of various body segments (e.g. hip, knee and ankle) to produce motion. Kinetic referring to motion, and chain being an analogy for the interdependent link between systems.

Example, the posterior kinetic chain, refers to the integrated function of nerves, muscles, fascia and joints on the posterior side of the body.

The concept of the kinetic chain was originally adapted from the work of a mechanical engineer named Franz Reuleaux (Kinematics of Machinery (1875)) by Dr. Arthur Steindler in 1955 (Steindler A: Kinesiology of the Human Body. Springfield, IL, Charles C. Thomas Co.. 1955).

Latent Trigger Point - A myofascial trigger point that is not painful at rest, only painful when palpated, and may or may not exhibit a characteristic referral pain pattern when palpated.  Latent trigger points do result in an acute point of sensitivity, in a taut band of muscle, and may restrict range of motion (1).

Note: Based on the clinical experience, the Brookbush Institute suggests that latent trigger points (sometimes refereed to as Tender Points) are more common than active trigger points. Further, they are likely addressed more often than trigger points; being the intended target of many soft-tissue mobility techniques.
<ol>
 	<li>David G. Simons, Janet Travell, Lois S. Simons, Travell &amp; Simmons’ Myofascial Pain and Dysfunction, The Trigger Point Manual, Volume 1. Upper Half of Body: Second Edition,© 1999 Williams and Wilkens</li>
</ol>

An anatomical direction; further from the midline

Example, the anterior deltoid is lateral to the pectoralis major

Length/Tension Relationship - The amount of force generated by a muscle is dependent on sarcomere length.
<ul>
 	<li>The ability of sarcomere to maximally produce force occurs when sarcomere length results in optimal overlap between actin and myosin. Stretching a sarcomere decreases overlap between actin and myosin filaments and reduces force production (1-3). When length is less than optimal, actin from opposite ends overlap and interfere with cross-bridging, and myosin filament are compressed as they contact the the Z-disk also reducing force (4)</li>
</ul>
<ol>
 	<li>Gordon, A. M., Huxley, A. F., &amp; Julian, F. J. (1966). The variation in isometric tension with sarcomere length in vertebrate muscle fibres. The Journal of physiology, 184(1), 170-192.</li>
 	<li>Edman, K. A. P. (1966). The relation between sarcomere length and active tension in isolated semitendinosus fibres of the frog. The Journal of Physiology, 183(2), 407-417.</li>
 	<li>Lieber, R. L., Loren, G. J., &amp; Friden, J. (1994). In vivo measurement of human wrist extensor muscle sarcomere length changes. Journal of neurophysiology, 71(3), 874-881.</li>
 	<li>Lieber, R. L. (2002). Skeletal muscle structure, function, and plasticity. Lippincott Williams &amp; Wilkins.</li>
</ol>
&nbsp;

Levels of Evidence - Relative to evidence-based practice, levels of evidence are an attempt to describe the strength of the results measured in a clinical trial or research study.  Note: levels of evidence do not supersede the critical evaluation of an experienced professional, and should be viewed as guidelines - a meta-analysis may be poorly constructed (Level IA), and a comparative study (Level III) may employ new technologies and a strong methodology.


The Levels of Evidence used by the Brookbush Institute, as described by Shekelle et al.(1):
<ul>
 	<li class="p1">IA - Evidence from meta-analysis of randomized controlled trials</li>
 	<li class="p1">IB - Evidence from at least one randomized controlled trial</li>
 	<li class="p1">IIA - Evidence from at least one controlled study without randomization</li>
 	<li class="p1">IIB - Evidence from at least one other type of quasi-experimental study</li>
 	<li class="p1">III - Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies, and case-control studies</li>
 	<li class="p1">IV - Evidence from expert committee reports or opinions or clinical experience of respected authorities, or both</li>
</ul>
<ol>
 	<li>Shekelle, P. G., Woolf, S. H., Eccles, M., &amp; Grimshaw, J. (1999). Developing clinical guidelines. Western Journal of Medicine, 170(6), 348.</li>
</ol>

Likelihood Ratios - Likilihood ratios are used for assessing the value of performing a diagnostic test. They use sensitivity and specificity to determine whether a test result usefully changes the practitioner's chance (probability) of reaching the correct assessment. Calculation of likelihood ratios is based on Baye's theorem.
<ul>
 	<li>Positive Likelihood Ratio (LR+) - The ratio of a positive test result in people with the pathology to a positive test result in people without the pathology.</li>
 	<li>Negative Likelihood Ratio (LR-) - The ratio of a negative test result in people with the pathology to a negative test result in people without the pathology.</li>
</ul>

Longitudinal Study - a research design that involves observing the same variables, several times over a period of time.
<ul>
 	<li>Example, the study by Hewett et al. (1) is a type of longitudinal study called a "cohort study." This study investigated whether excessive knee valgus during landing was a predictor of knee injury risk in adolescent females over the course of a season.</li>
</ul>
<ol>
 	<li><a href="https://brentbrookbush.com/articles/research-corner/knee/research-review-increased-valgus-during-landing-predicts-acl-injury-in-adolescent-female-athletes/" target="_blank" rel="noopener noreferrer">Hewett, T. E., Myer, G. D., Ford, K. R., Heidt, R. S., Colosimo, A. J., McLean, S. G., &amp; Succop, P. (2005). Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes A prospective study. The American journal of sports medicine, 33(4), 492-501</a></li>
</ol>

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