Introduction: Kinetic Response During Landing of Plyometric Exercises

How Does this Relate to Brookbush Institute Content: Kinetic Quantification of Plyometric Exercise Intensity

Introduction: Quantifying Plyometric Exercise Intensity via Rate of Eccentric Force Development

Study Summary: Quantifying Plyometric Exercise Intensity via Rate of Eccentric Force Development

How this Study Contributes to the Body of Research: Quantifying Plyometric Exercise Intensity via Rate of Eccentric Force Development

How the Findings Apply to Practice: Quantifying Plyometric Exercise Intensity via Rate of Eccentric Force Development

How Does this Relate to Brookbush Institute Content: Quantifying Plyometric Exercise Intensity via Rate of Eccentric Force Development

Introduction: Quantifying of Vertical Ground Reaction Forces of Plyometric Exercises

Study Summary: Quantifying of Vertical Ground Reaction Forces of Plyometric Exercises

How this Study Contributes to the Body of Research: Quantifying of Vertical Ground Reaction Forces of Plyometric Exercises

How the Findings Apply to Practice: Quantifying of Vertical Ground Reaction Forces of Plyometric Exercises

Study Summary: Kinetic Response During Landing of Plyometric Exercises

How Does this Relate to Brookbush Institute Content: Quantifying of Vertical Ground Reaction Forces of Plyometric Exercises

How this Contributes to the Body of Research: Kinetic Response to Plyometric Exercises

How the Findings Apply to Practice: Kinetic Response During Landing of Plyometric Exercises

How Does this Relate to Brookbush Institute Content: Kinetic Response During Landing of Plyometric Exercises

Introduction: Kinetic Quantification of Plyometric Exercise Intensity

Study Summary: Kinetic Quantification of Plyometric Exercise Intensity

How this Study Contributes to the Body of Research: Kinetic Quantification of Plyometric Exercise Intensity

How the Findings Apply to Practice: Kinetic Quantification of Plyometric Exercise Intensity

Lower Extremity Power Exercise Intensity: Part 1

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Lower-extremity Power Exercise Intensity, Part 1..

Jensen et al. (2008). Kinetic Response During Landing of Plyometric Exercises

Original Citation: Jensen, R.L., Flanagan, E.P., Jensen, N.L. and Ebben, W.P. (2008). Kinetic responses during landings of <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises. Journal of Strength &amp; Conditioning Research, 393-396. - <a href="https://ojs.ub.uni-konstanz.de/cpa/article/view/1865" target="_blank" rel="noopener">Abstract</a>
Why the Study is Relevant: Studies have demonstrated that training with <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises is effective for improving performance of high-velocity (<a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a>) activities; however, few studies have attempted to quantify and compare the intensity of <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises. This 2008 study by American researchers compared common <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises based on landing impulse and peak <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>). Based on the forces observed, the findings suggest that the exercises may be ranked from lowest to highest: cone hop, single-leg jump, drop jump 60cm, tuck jump, counter-movement jump (CMJ), squat jump 30% 1-RM, and drop jump 30cm.
<a href="https://www.datocms-assets.com/25800/1645724142-lateral-hop-to-single-leg-vertical-to-balance.png"><img src="https://www.datocms-assets.com/25800/1645724142-lateral-hop-to-single-leg-vertical-to-balance.png" width="419" height="458"></a>

Introduction

<table>
 <tbody>
 <tr>
 <td width="40%">Design</td>
 <td>Randomized order, repeated-measures, comparative study</td>
 </tr>
 <tr>
 <td>Level of Evidence</td>
 <td>III Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies, and case-control studies</td>
 </tr>
 <tr>
 <td>Participant Characteristics</td>
 <td>
 <ul>
 <li>Gender: 8 males</li>
 <li>Age &#xB1; Standard Deviation (years): 20.02 &#xB1; 2.1</li>
 <li>Body Mass &#xB1; Standard Deviation (kilograms) = 82.3 &#xB1;14.9</li>
 <li>Characteristics: Participants were familiarized with the <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises</li>
 </ul>
 Inclusion Criteria:
 <ul>
 <li>National Collegiate Athletic Association (NCAA) Division-1 track and field athletes</li>
 </ul>
 Exclusion Criteria:
 <ul>
 <li>N/A</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Methodology</td>
 <td>
 <ul>
 <li><a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercises included: countermovement jump (CMJ), drop jump from 30cm and 60cm (DJ30, DJ60), cone hop (CH), tuck jump (TJ), single-leg counter movement jump using dominant leg (SLJ) and squat jump (SJ30).</li>
 <li>All participants performed a standard warm-up prior to data collection.</li>
 <li>A 1-minute rest interval ensured sufficient recovery between jumps.</li>
 </ul>
 Standardization
 <ul>
 <li>30cm and 60cm drop jump: Participants stepped forward off the box without stepping down or jumping up, and upon contact with the force platform jumped as high and as quickly as possible.</li>
 <li>Cone hop: Participants jumped laterally and as quickly as possible over a 15cm tall cone.</li>
 <li>All other jumps: Participants jumped as high as possible.</li>
 <li>For all exercises, arm position was not controlled in order to maintain ecological <a id="validity" data-tip="1511" target="_blank" href="/glossary-term/validity" class="glossary">validity</a>.</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Data Collection and Statistical Analysis</td>
 <td>
 <ul>
 <li><a id="ground-reaction-force" data-tip="1395" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">Ground reaction force</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>) measurements were obtained using a force plate sampling at 1000Hz
 <ul>
 <li>For drop jumps, only the landing component was considered.</li>
 </ul>
 
 </li>
 </ul>
 </td>
 </tr>
 <tr>
 <td> Outcome Measures</td>
 <td>
 <ul>
 <li>Peak <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> was defined as the peak force during the landing portion of the <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise</li>
 <li>Total landing impulse was calculated as the total <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> from point of landing until the vertical force component reached the participant&#x2019;s body mass after peak GRF</li>
 <li>Mean landing impulse was calculated as the total landing impulse divided by the time of impulse</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Results</td>
 <td>
 <ul>
 <li>Significant differences were observed between some <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises (P&lt;0.05).</li>
 </ul>
 GRF:
 <ul>
 <li>The single-leg jump resulted in significantly lower <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> than the drop jump 30cm and squat jump 30%RM</li>
 <li>The squat jump 30cm was significantly greater than the cone hop and the single-leg jump</li>
 </ul>
 Total Landing Impulse:
 <ul>
 <li>The single-leg jump resulted in a significantly lower landing impulse than the drop jump 60cm and the squat jump 30% 1-RM.</li>
 <li>The squat jump 30% 1-RM resulted in a significantly larger landing impulse than the cone hop and the single-leg jump</li>
 </ul>
 Mean Landing Impulse:
 <ul>
 <li>The single-leg jump resulted in a significantly lower landing impulse than the drop jump 30cm, the tuck jump and the squat jump 30% 1-RM.</li>
 <li>The squat jump 30%RM resulted in a significantly larger landing impulse than the drop jump 60cm and the single-leg jump.</li>
 </ul>
 
 Intensity Ranking Continuum:
 Landing Peak <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> (Newtons) (Low-High):
 <ol>
 <li>Cone hop (2,207.5)</li>
 <li>Single leg jump (2,208.4)</li>
 <li>Drop jump 60cm (2,431.1)</li>
 <li>Tuck jump (2,570.4)</li>
 <li>Countermovement jump (2,597.2)</li>
 <li>Squat jump 30%RM (2,766.1)</li>
 <li>Drop jump 30cm (2,837.9)</li>
 </ol>
 Total Landing Impulse (N.s):
 <ol>
 <li>Cone hop (418,981.2)</li>
 <li>Single leg jump (481,135.4)</li>
 <li>Drop jump 30cm (560,080.3)</li>
 <li>Drop jump 60cm (573,914.7)</li>
 <li>Tuck Jump (624,575.6)</li>
 <li>Countermovement jump (651,880.4)</li>
 <li>Squat jump 30%RM (791,471.7)</li>
 </ol>
 Mean Landing Impulse (N.s):
 <ol>
 <li>Single leg jump (1,132.0)</li>
 <li>Countermovement jump (1,242.6)</li>
 <li>Cone hop (1,252.6)</li>
 <li>Drop jump 60cm (1,258.1)</li>
 <li>Drop jump 30cm (1,314.4)</li>
 <li>Tuck jump (1,326.4)</li>
 <li>Squat jump 30%RM (1,496.9)</li>
 </ol>
 </td>
 </tr>
 <tr>
 <td>Our Conclusions</td>
 <td>Plyometric exercises should be carefully selected and integrated into a progressive, periodized program. This study provides human movement professionals with an evidence-based for progressing plyometric exercise based on intensity (landing impulse and GRF).</td>
 </tr>
 <tr>
 <td>Researchers&apos; Conclusions
 
 </td>
 <td>An enhanced understanding of landing intensity in plyometric exercises is important for structuring effective training programs. This study provides additional data and variables for consideration of plyometric exercise intensity.</td>
 </tr>
 </tbody>
</table>
<a href="https://www.datocms-assets.com/25800/1645724305-single-leg-box-jump.jpeg"><img src="https://www.datocms-assets.com/25800/1645724305-single-leg-box-jump.jpeg"></a>

Study Summary

The selection and <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progression</a> of <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise is often based on subjective feelings or is reliant on a coach&apos;s experience without quantifiable data to <a id="base-of-support" data-tip="1197" target="_blank" href="/glossary-term/base-of-support" class="glossary">support</a> the selection. Most <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> training research investigates the effectiveness of <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> training programs, without direct comparison of the <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> exercises within a program. This study demonstrated that landing impulse and <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>) were significantly different for different <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises. For example, the single-leg jump resulted in significantly lower <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> than the drop jump 30cm and squat jump 30% 1-RM, and the squat jump 30% 1-RM resulted in significantly greater <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> than the cone hop and the single-leg jump. This objective data may aid in the selection and <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progression</a> of <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> activity.

How This Study Contributes to the Body of Research

The findings of this study imply a ranking of <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise based on landing impulse and <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>. Coaches may use these findings to aid in selecting the appropriate <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise based on an athlete&apos;s ability, and then progress that <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> activity based on intensity. The findings of this study imply the following order from lowest to highest intensity (forces):
<ul>
 <li>Cone hop</li>
 <li>Single leg jump</li>
 <li>Drop jump 60cm</li>
 <li>Tuck jump</li>
 <li>Countermovement jump</li>
 <li>Squat jump 30% RM</li>
 <li>Drop jump 30cm</li>
</ul>
Strengths:
<ul>
 <li>The study used common <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises which improves the applicability of study findings to practice.</li>
 <li>Measurements of <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> were carried out using validated technology (force plate B600-1200), enhancing the <a id="accuracy" data-tip="1218" target="_blank" href="/glossary-term/accuracy" class="glossary">accuracy</a> and confidence in study findings.</li>
 <li>The experimental protocol reduced the potential effect fatigue may have on findings, including randomizing the sequence of exercises performed.</li>
</ul>
Weaknesses and Limitations:
<ul>
 <li>The limited number of exercises used, and the limited number of variables measured, make it hard to hypothesize about &quot;the why&quot; of varied intensities.</li>
 <li>The use of a small population of high-level (Division I) athletes, may reduce the generalizability of findings.</li>
 <li>Exclusion criteria were missing from this study, including injury history.</li>
 <li>The use of mean values may the study to a high degree of sampling error, particularly when standard deviations are high.</li>
</ul>

How the Findings Apply to Practice

The Brookbush Institute (BI) continues to develop and refine recommendations for <a href="https://brookbushinstitute.com/article/introduction-power-training-high-velocity-training" target="_blank" rel="noopener">power training</a>. This study demonstrated that there is a significant difference between <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise based on landing impulse and <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a>. The BI has <a id="integration" data-tip="1473" target="_blank" href="/glossary-term/integration" class="glossary">integrated</a> these findings into recommendations for the <a href="https://brookbushinstitute.com/article/power-training-lower-body-exercises" target="_blank" rel="noopener">lower body </a><a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> exercise progression. The BI will continue to pursue <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> practice by refining <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> exercise recommendations, using the aggregated results of all available original research.
<h3>For more information check out:</h3>
<ul>
 <li><a href="https://brookbushinstitute.com/course/power-training-lower-body-exercises">Power (High-velocity) Training: Lower Body</a></li>
</ul>

How Does this Relate to Brookbush Institute Content

<h3>Box Jump</h3>
<iframe src="https://player.vimeo.com/video/247962609" frameborder="0" allowfullscreen="allowfullscreen"></iframe>
Single leg box jump
<iframe src="https://player.vimeo.com/video/156507319" frameborder="0" allowfullscreen="allowfullscreen"></iframe>
Tuck Jump
<iframe src="https://player.vimeo.com/video/247970293" frameborder="0" allowfullscreen="allowfullscreen"></iframe>

Bibliography

Ebben, et al. (2011). Kinetic Quantification of Plyometric Exercise Intensity

Original Citation: Ebben, W.P., Fauth, M.L., Garceau, L.R. and Petushek, E.J. (2011). Kinetic quantification of <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise intensity. Journal of Strength &amp; Conditioning Research, 25(12), 3288-3298. - <a href="https://www.ncbi.nlm.nih.gov/pubmed/22080319" target="_blank" rel="noopener">Abstract</a>
<h3>Why the Study is Relevant:</h3>
<a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> training is recommended to improve sports performance with the intent of increasing the rate of force development (RFD) (1); however, few studies have compared <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercises based on objective data. This 2011 study by American researchers compared eight lower-extremity <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercises based on <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>) and <a id="assessment" data-tip="1481" target="_blank" href="/glossary-term/assessment" class="glossary">evaluation</a> of gender differences. The findings of this study suggest high RFD <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercises, like cone hops and tuck jumps, result in larger <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> than slower RFD exercises like single-leg jumps and dumbbell jumps.
<a href="https://www.datocms-assets.com/25800/1645724226-boxjump.jpeg"><img src="https://www.datocms-assets.com/25800/1645724226-boxjump.jpeg"></a>

<table>
 <tbody>
 <tr>
 <td width="40%">Study Design</td>
 <td>Randomized order, repeated-measures, comparative study</td>
 </tr>
 <tr>
 <td>Level of Evidence</td>
 <td>III Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies, and case-control studies</td>
 </tr>
 <tr>
 <td>Subject Characteristics</td>
 <td>
 <ul>
 <li>Age &#xB1; Standard Deviation (in years): Men = 20.23 &#xB1; 1.63, Women = 20.39 &#xB1; 1.50</li>
 <li>Gender: 26 Men, 23 Women</li>
 <li>Characteristics: <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> training (d.wk-1) = 1.43&#xB1;1.40/Resistance training (d.wk-1) = 2.65&#xB1;1.2.</li>
 </ul>
 Inclusion Criteria:
 <ul>
 <li>Subject involvement in the National Collegiate Athletic Association (NCAA) Division-1, club, or recreational sports, and participation in <a id="plyometric" data-tip="1296" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometrics</a> as part of their annual training program.</li>
 </ul>
 Exclusion Criteria:
 <ul>
 <li>Orthopedic lower limb injury, known cardiovascular pathology, or contraindications to resistance or <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> training.</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Methodology</td>
 <td>
 <ul>
 <li><a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> Exercises Included: Line hop (LH), cone hop (CH), squat jump (SJ), tuck jump (TJ), countermovement jump (CMJ), dumbbell jump (DBJ) (dumbbells, 30%RM), drop jump (DJ) and single-leg jump (SLJ). Exercise characteristics were based on previously published procedures (8).</li>
 <li>Drop jump height was normalized to subjects previously assessed CMJ height.</li>
 </ul>
 All subjects performed both a habituation and testing session.
 Habituation
 <ul>
 <li>Subjects were given instruction and a demonstration on the correct performance of the <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises to be assessed during the habituation session. These exercises were performed as previously described in Essentials of Strength Training and Conditioning (2).</li>
 <li>The habituation session consisted of a warm-up, 2 repetitions of the CMJ, and a 5RM back squat <a id="assessment" data-tip="1482" target="_blank" href="/glossary-term/assessment" class="glossary">test</a>, all separated by a 4-minute recovery period. Subjects performed each <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise until they mastered the correct technique during the habituation session.</li>
 <li>After the habituation session, subjects recovered for at least 48 hours prior to returning for the testing session.</li>
 </ul>
 Testing
 <ul>
 <li>During the testing session, subjects performed the same warm-up protocol as used during habituation session, followed by 5-minutes of recovery.</li>
 <li>The back squat <a id="assessment" data-tip="1482" target="_blank" href="/glossary-term/assessment" class="glossary">test</a> included 2 warm-up sets of 3 repetitions at approximately 75% and 90% of the subjects estimated maximum ability. The 5RM back squat was then performed in alignment with previous methods prescribed (3). 5RM back squat <a id="assessment" data-tip="1482" target="_blank" href="/glossary-term/assessment" class="glossary">test</a> was carried out to determine 30%1-RM load for the dumbbell jump (DBJ) exercise.</li>
 <li>Subjects performed 3 repetitions of each <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise.</li>
 <li>The exercise selection order was randomized with 1-minute rest between each exercise. The recovery duration between reps and sets was based on a ratio of at least 1:5.</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Data Collection &amp; Statistical Analysis:</td>
 <td>
 <ul>
 <li>Data was collected using a 60x120cm force platform set at 1000Hz.</li>
 <li>Women subjects demonstrated 1RM back squat strength and vertical jump ability 69.1% and 75.5% respectively, of the values of men.</li>
 <li>A 2-way mixed analysis of variance (ANOVA) with repeated measure, for <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise type was carried out to evaluate main effects of exercise type and interaction between type and gender.</li>
 <li>Bonferroni adjusted pairwise comparison for identification of <a id="specificity" data-tip="1224" target="_blank" href="/glossary-term/specificity" class="glossary">specific</a> differences between <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises.</li>
 <li>A repeated-measures ANOVA confirmed no significance between 3 trials of each <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise.</li>
 <li>Pearson&apos;s correlation coefficient was used to <a id="assessment" data-tip="1486" target="_blank" href="/glossary-term/assessment" class="glossary">assess</a> the relationship between JH and L-RFD and GRF-L for each <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise.</li>
 <li>Independent samples t-tests were used to <a id="assessment" data-tip="1486" target="_blank" href="/glossary-term/assessment" class="glossary">assess</a> baseline gender differences in subject strength and jumping ability.</li>
 <li>Significance was specified as (P&lt;0.05).</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Outcome Measures </td>
 <td>
 <ul>
 <li>Peak vertical <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>) - the highest vertical <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> value attained from the force-time record for the take-off phase of each jump.</li>
 <li>Peak vertical <a id="ground-reaction-force" data-tip="1395" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction force</a> minus body mass during the take-off phase of the <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises (GRF-T) - the highest vertical <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> value attained from the force-time record for the take-off phase of each jump. minus body-weight.</li>
 <li>Time to take off (TTT) - the time of onset of the flight phase minus the time of onset of the eccentric phase from the force-time record.</li>
 <li>Flight time (FT) - the period after the take-off phase and before the landing phase where the <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> equaled zero.</li>
 <li>Jump height (JH) - calculated from the force-time records consistent with methods used in prior research (4).</li>
 <li>Peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> (P) - calculated using the Canavan and Vescovi equation (5).</li>
 <li>The loading rate of force development (L-RFD) - the first peak of <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> minus the time to initial <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>, divided by the time to first peak of <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>, minus the time of initial <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>.</li>
 <li>Peak vertical <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> minus body mass during the landing phase (GRF-L) - highest vertical <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> value attained during the landing phase of the <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise, minus body mass.</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Results</td>
 <td>
 <ul>
 <li>GRF: Significant differences were observed between <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises, and for the interaction between <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises and gender</li>
 <li>GRF-T, TTT, FT, JH, P, L-RFD, GRF-L: Significant differences observed between exercises; however, no significant effects for the interaction between <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises and gender</li>
 </ul>
 Exercise Continuum of Intensity (Low-High):
 Drop Jump GRF-T was not measured. This was likely due to the complications of comparing the GRF-T to other measures due to the added force from the acceleration due to gravity, increased time on the platform, and landing <a id="reliability" data-tip="1515" target="_blank" href="/glossary-term/reliability" class="glossary">reliability</a> on the platform.
 Male:
 <ul>
 <li>Based on explosive muscular force production (GRF-T)* - Single leg jump (SLJ), squat jump (SJ), dumbbell jump (DBJ), Line hop (LH), countermovement jump (CMJ), tuck jump (TJ), cone hop (CH)</li>
 </ul>
 Female:
 <ul>
 <li>Based on explosive muscular force production (GRF-T)* - SLJ, DBJ, SJ, CMJ, LH, TJ, CH</li>
 </ul>
 All Subjects:
 <ul>
 <li>Based on reactive strength index (RSI), stretch-shortening cycle duration (TTT) &#x2013; DBJ, SLJ, CMJ, TJ, SJ, DJ, CH, LH</li>
 <li>Based on <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> production (P) &#x2013; LH, CH, SLJ, SJ, TJ, CMJ, DJ, DBJ</li>
 <li>Based on biomaterial loading (L-RFD) &#x2013; LH, CH, SLJ, TJ, SJ, DBJ, CMJ, DJ</li>
 <li>Based on intensity for magnitude of compressive strain (GRF-L) &#x2013; LH, CH, SLJ, SJ, TJ, CMJ, DBJ, DJ</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Our Conclusions</td>
 <td>Plyometric exercises should be carefully selected and integrated into a progressive, periodized program. This study provides human movement professionals with an evidence-base for progressing plyometric exercise based on intensity (GRF).</td>
 </tr>
 <tr>
 <td>Researchers&apos; Conclusions</td>
 <td>Female and male subjects respond similarly. Differences in kinetic characteristics among exercises establish a hierarchy of intensity for sport/exercise training purposes.</td>
 </tr>
 </tbody>
</table>
<a href="https://brookbush.s3.us-east-2.amazonaws.com/wordpress/wp-content/uploads/2017/10/lateral-hop-to-single-leg-box-ju.jpg" target="_blank" rel="noopener"><img src="https://brookbush.s3.us-east-2.amazonaws.com/wordpress/wp-content/uploads/2017/10/lateral-hop-to-single-leg-box-ju.jpg" alt></a>

<a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercises are often selected based on their relative intensity; however, human movement professionals often determine intensity based on experience or anecdotal evidence (2). There is a growing body of research quantifying <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercise intensity, and this study adds an in-depth comparison of <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercises based on <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>). The findings of this study suggest high-RFD <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercises, like cone hops and tuck jumps, result in larger <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> than slower RFD exercises, like single-leg jumps and dumbbell jumps. Further, jump height was not a good predictor of <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>. This objective data may aid in the selection and <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progression</a> of <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> activity.

How this Study Contributes to the Body of Research

This study provides objective data on peak <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>) for eight commonly performed <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises. Findings from this study may have implications for exercise selection and <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progression</a>, and imply the following order from lowest to highest <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>. Note, gender differences were largely insignificant; however, some significant variations in <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> during the take-off phase were noted.
Recommended <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">Progression</a> of <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> Exercise based on GRF-T
<table>
 <tbody>
 <tr>
 <td>Male</td>
 <td>Female</td>
 </tr>
 <tr>
 <td>
 <ul>
 <li>Single leg jump (SLJ)</li>
 <li>Squat jump (SJ)</li>
 <li>Dumbbell jump</li>
 <li>Line hop (LH)</li>
 <li>Countermovement jump (CMJ)</li>
 <li>Tuck jump (TJ)</li>
 <li>Cone hop (CH)</li>
 <li>Depth Jump (DJ)</li>
 </ul>
 </td>
 <td>
 <ul>
 <li>Single leg jump (SLJ)</li>
 <li>Dumbell jump (DJ)</li>
 <li>Squat jump (SJ)</li>
 <li>Countermovement jump (CMJ)</li>
 <li>Line hop (LH)</li>
 <li>Tuck jump</li>
 <li>Cone hop (CH)</li>
 <li>Depth Jump (DJ)</li>
 </ul>
 </td>
 </tr>
 </tbody>
</table>
Strengths:
<ul>
 <li>Randomization of exercise order and adequate rest periods (work-to-rest ratios of at least 1:5) reduced the potential influence of fatigue.</li>
 <li>The exercises included in the study are commonly used in strength and conditioning programs to improve performance, increasing the applicability of study results.</li>
 <li>The study included a variety of measurements that aided in developing a detailed account of forces and correlated factors, likely improving the <a id="validity" data-tip="1511" target="_blank" href="/glossary-term/validity" class="glossary">validity</a> and <a id="accuracy" data-tip="1218" target="_blank" href="/glossary-term/accuracy" class="glossary">accuracy</a> of study conclusions.</li>
</ul>
Weaknesses and Limitations:
<ul>
 <li>Peak <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> was calculated using only the Canavan and Vescovi equation; some research suggests that equations such as that produced by Harman may be more accurate (5). The use of other equations may produce a different <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> output value, which could affect the degree of significance.</li>
 <li>Exclusion criteria did not include movement <a id="assessment" data-tip="1478" target="_blank" href="/glossary-term/assessment" class="glossary">assessment</a> to identify potential musculoskeletal limitations.</li>
 <li>The study included very high-level athletes (Division I), which may reduce the generalizability of the findings to other populations.</li>
</ul>

The Brookbush Institute (BI) encourages &quot;progressions&quot; for all aspects of a program. This includes the <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progression</a> from isolated <a id="activation-technique" data-tip="1531" target="_blank" href="/glossary-term/activation-technique" class="glossary">activation techniques</a> to reactive <a id="activation-technique" data-tip="1530" target="_blank" href="/glossary-term/activation-technique" class="glossary">activation exercises</a>, the <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progression</a> of strength exercises from stable to less stable, stability/endurance training to max strength/power training, and the <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progression</a> of the intensity of plyometric/power exercises over time. This study&#x2019;s findings suggest that human movement professionals may need to consider <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>) when selecting and progressing <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> exercises; and further, that jump height and gender are unlikely to significantly influence selection. The BI has <a id="integration" data-tip="1473" target="_blank" href="/glossary-term/integration" class="glossary">integrated</a> these findings into recommendations for <a href="https://brookbushinstitute.com/article/power-training-lower-body-exercises" target="_blank" rel="noopener">Power Exercise Progressions: Lower Body</a>. The BI will continue to pursue <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> practice by refining <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> exercise recommendations, using the aggregated results of all available original research.
<h3>For more information check out:</h3>
<ul>
 <li><a href="https://brookbushinstitute.com/course/power-training-lower-body-exercises" target="_blank" rel="noopener">Power (High-velocity) Training: Lower Body</a></li>
</ul>

<h3>Box Jumps</h3>
<iframe src="https://player.vimeo.com/video/247962609" frameborder="0" allowfullscreen="allowfullscreen"></iframe>
<h3>Lateral Hop to Single-leg Vertical to Balance</h3>
<iframe src="https://player.vimeo.com/video/156491756" frameborder="0" allowfullscreen="allowfullscreen"></iframe>
<h3>Multi-Planer Skaters</h3>
<iframe src="https://player.vimeo.com/video/127463614" frameborder="0" allowfullscreen="allowfullscreen"></iframe>

<ol>
 <li>Markovic, G. (2007). Does plyometric training improve vertical jump height? A meta-analytical review. British Journal of Sports Medicine, 41, 349-355.</li>
 <li>Potach, DH. and Chu, DA. (2008). Plyometric training. In: Essentials of Strength Training and Conditioning (3rd ed). In: T.R. Baechle and R.W. Earle, eds. Champaign, IL: Human Kinetics, 413-437.</li>
 <li>Baechle, TR., Earle, RW. and Wathen, D. Resistance training. In: Essentials of Strength Training and Conditioning (3rd ed.). T.R. Baechle and R.W. Earle, eds. Champaign, IL: Human Kinetics, 2008. pp. 381-412.</li>
 <li>Moire, G. (2008). Three different methods of calculating vertical jump from force platform data in men and women. Measurement in Physical Education and Exercise Science, 12: 207-218.</li>
 <li>Canavan, PK. Vescovi, JD. (2004). Evaluation of power prediction equations: peak vertical jumping power in women. Medicine &amp; Science in Sports &amp; Exercise, 36(9), 1589-1593.</li>
 <li>Chmielewski, TL., Myer, GD., Kauggman, D. and TIllman, SM. (2006). Plyometric exercise in the rehabilitation of athletes: Physiological responses and clinical application. Journal of Orthopaedic and Sports Physical Therapy, 36, 208-319.</li>
</ol>

Jensen et al. (2007). Quantifying Plyometric Exercise Intensity via Rate of Eccentric Force Development

Original Citation: Jensen, RL. and Ebben, WP. (2007). Quantifying <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise intensity via rate of force development, knee joint, and <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a>. Journal of Strength and Conditioning Research, 21(3), 763-767. <a href="https://www.ncbi.nlm.nih.gov/pubmed/17685678" target="_blank" rel="noopener">Abstract</a>
<h3>Why the Study is Relevant:</h3>
<a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercises are recommended for improving <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> and enhancing sports performance (1); however, relatively few research studies have compared <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercises. This 2007 study by American researchers quantified the intensity of eight lower-extremity <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercises based on the <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>), knee joint reaction forces, and eccentric rate of force development (E-RFD). The findings imply the following order from lowest to highest E-RFD: Dumbbell squat jump (30% 1-RM), Squat jump, Pike jump, Single leg jump, Depth jump (46cm), Tuck jump, Countermovement jump, Depth jump (61cm).
<a href="https://brookbush.s3.us-east-2.amazonaws.com/wordpress/wp-content/uploads/2016/12/single-leg-box-jump.jpg" target="_blank" rel="noopener"><img src="https://brookbush.s3.us-east-2.amazonaws.com/wordpress/wp-content/uploads/2016/12/single-leg-box-jump-300x169.jpg" alt></a>
The Single-Leg Jump <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> Exercise - Courtesy of the Brookbush Institute

<table>
 <tbody>
 <tr>
 <td width="40%">Design</td>
 <td>Randomized order, repeated-measures, comparative study</td>
 </tr>
 <tr>
 <td>Level of Evidence</td>
 <td>III Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies, and case-control studies</td>
 </tr>
 <tr>
 <td>Participant Characteristics</td>
 <td>Demographics
 <ul>
 <li>Age (&#xB1; standard deviation, in years): 20.3 &#xB1; 1.0</li>
 <li>Gender: 4 female, 2 male</li>
 <li>Body Mass: 78.9 &#xB1; 12.2 kg</li>
 <li>1 Repetition Maximum Squat (1-RM): 143.6 &#xB1; 55.6 kg</li>
 </ul>
 Inclusion Criteria:
 <ul>
 <li>National Collegiate Athletic Association Division I athlete in track and field, volleyball or wrestling</li>
 <li>Regular practice of <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises, similar to those investigated in this study</li>
 </ul>
 Exclusion criteria:
 <ul>
 <li>N/A</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Methodology</td>
 <td>
 No strength training 48 hours prior to data collection
 All participants completed a warm-up consisting of:
 <ul>
 <li>At least 3 minutes of low-intensity work on a cycle ergometer</li>
 <li>Static stretching, including 1 exercise for every major <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> group (15 sec. holds)</li>
 <li>An activity-specific dynamic warm-up</li>
 <li>5-minute post warm-up recovery</li>
 </ul>
 In the <a id="assessment" data-tip="1482" target="_blank" href="/glossary-term/assessment" class="glossary">test</a> protocol:
 <ul>
 <li>Participants were randomly assigned to complete 8 <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises.</li>
 <li>A 1-minute rest interval was permitted between exercises to minimize fatigue.</li>
 <li>As they exercised, participants were videotaped from the left side at 60Hz, with joint markers at the greater trochanter, center of knee joint, <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> malleolus and fifth metatarsal</li>
 </ul>
 Outcome measures:
 <ul>
 <li>Peak <a id="ground-reaction-force" data-tip="1395" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">Ground Reaction Force</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>): measured at landing and defined as highest value recorded</li>
 <li>Rate of Eccentric force Development (E-RFD): defined as the first peak of <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> data divided by the time from onset of landing force to the first peak of <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> (3)</li>
 <li>Knee Joint Reaction Forces (K-JRF): estimated according to a previously researched method (3)</li>
 <li><a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> was divided in half to calculate K-JRF in the single-leg jumps</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Data Collection and Statistical Analysis</td>
 <td>
 <ul>
 <li>Data was calculated using a 1-way (type of <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise) repeated measures analysis of variance for average E-RFD, <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>, GRF/BW, K-JRF and K-JRF/BW (P&lt;0.05)</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Results</td>
 <td>
 Differences in peak <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>) and peak ground reaction forces/bodyweight (GRF/BW) were not statistically significant, despite large variations in participants&#x2019; body weights (P&gt;0.05)
 Peak <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> ranking (low-high):
 <ol>
 <li>Single (left) Leg Jump</li>
 <li>Squat Jump (hands on top of head)</li>
 <li>Depth Jump (46cm)</li>
 <li>Pike Jump</li>
 <li>Countermovement Jump (with arm swing)</li>
 <li>Tuck Jump</li>
 <li>Dumbbell Squat Jump (30% rep max)</li>
 <li>Depth Jump (61cm)</li>
 </ol>
 The rate of eccentric force development (E-RFD) was significantly lower for the squat jump and the dumbbell squat jump (30% rep max) than for the depth jump, countermovement jump, single leg jump and tuck jump (P&lt;0.05)
 Peak E-RFD ranking (low-high):
 <ol>
 <li>Dumbbell Squat Jump (30% rep max)</li>
 <li>Squat Jump (hands top of head)</li>
 <li>Pike Jump</li>
 <li>Single (left) leg Jump</li>
 <li>Depth Jump (46cm)</li>
 <li>Tuck Jump</li>
 <li>Countermovement Jump (with arm swing)</li>
 <li>Depth Jump (61cm)</li>
 </ol>
 Differences in peak knee joint reaction force (K-JRF) and knee joint reaction force/bodyweight (K-JRF/BW) were statistically significant varied across <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises (P&lt;0.05).
 Peak K-JRF ranking (low-high):
 <ol>
 <li>Dumbbell Squat Jump (30% rep max)</li>
 <li>Countermovement Jump (with arm swing)</li>
 <li>Depth Jump (61cm)</li>
 <li>Depth Jump (46cm)</li>
 <li>Squat Jump (hands top of head)</li>
 <li>Single (left) leg Jump</li>
 <li>Pike Jump</li>
 <li>Tuck Jump</li>
 </ol>
 </td>
 </tr>
 <tr>
 <td>Our Conclusions</td>
 <td>This study demonstrated statistically significant differences in rate of eccentric force development (E-RFD) and knee joint reaction force (K-JRF) when comparing plyometric exercises. Human movement professionals may consider using the data from this study to aid in the selection and progression of plyometric exercises. Interestingly, GRF did not vary significantly between plyometric exercises, even with athletes of different body mass.</td>
 </tr>
 <tr>
 <td>Researchers&apos; Conclusions
 
 </td>
 <td>E-RFD and K-JRF are important variables to consider when quantifying the intensity of plyometric exercises performed by athletic populations. Although GRF did not differ significantly among exercises, it may be of importance in non-athletic populations and clinical populations.</td>
 </tr>
 </tbody>
</table>
<a href="https://brookbush.s3.us-east-2.amazonaws.com/wordpress/wp-content/uploads/2017/03/SL-Jump.png" target="_blank" rel="noopener"><img src="https://brookbush.s3.us-east-2.amazonaws.com/wordpress/wp-content/uploads/2017/03/SL-Jump-300x161.png" alt></a>
The Single-Leg <a id="lateral" data-tip="1567" target="_blank" href="/glossary-term/lateral" class="glossary">lateral</a> Jump <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> Exercise - Courtesy of the Brookbush Institute

This study adds to a growing body of research quantifying <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise intensity, including quantifying joint <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> absorption, time to stabilization, <a id="muscle-cell" data-tip="1781" target="_blank" href="/glossary-term/muscle-cell" class="glossary">muscle</a> activity, biomechanics, kinetic variables and exercise parameters (2-7). This study investigated <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>), knee joint reaction forces (K-JRF), and eccentric rate of force development (E-RFD) in various <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises. <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> were not significantly different between exercises. E-RFD was significantly lower for the squat jump and the dumbbell squat jump (30% rep max) than for the depth jump, counter-movement jump, single leg jump and tuck jump. Exercises that required rapid foot adjustment and/or <a id="unilateral" data-tip="1551" target="_blank" href="/glossary-term/unilateral" class="glossary">unilateral</a> stances produced higher K-JRF; however, higher K-JRF did not correlate with higher E-RFD. This objective data may aid in determining what factors should be used to select and progress exercise based on intensity.

This study provides data on peak <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>), rate of eccentric force development (E-RFD) and knee joint reaction forces (K-JRF) for commonly used <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises. Findings from this study may have implications for exercise selection based on eccentric load or joint &quot;health&quot;, and further, suggest that <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> may not be a <a id="reliability" data-tip="1795" target="_blank" href="/glossary-term/reliability" class="glossary">reliable</a> indicator of exercise intensity. Note, despite the inclusion of a <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progression</a> below, the difference between exercises was not statistically significant.
<table>
 <tbody>
 <tr>
 <td>Peak GRF (low-high):</td>
 <td>Peak E-RFD (low-high):</td>
 <td>Peak K-JRF (low-high)</td>
 </tr>
 <tr>
 <td>
 <ol>
 <li>Single leg jump</li>
 <li>Squat jump</li>
 <li>Depth jump (46cm)</li>
 <li>Pike jump</li>
 <li>Countermovement jump</li>
 <li>Tuck jump</li>
 <li>Dumbbell squat jump</li>
 <li>Depth jump (61cm)</li>
 </ol>
 </td>
 <td>
 <ol>
 <li>Dumbbell squat jump (30%RM)</li>
 <li>Squat jump</li>
 <li>Pike jump</li>
 <li>Single leg jump</li>
 <li>Depth jump (46cm)</li>
 <li>Tuck jump</li>
 <li>Countermovement jump</li>
 <li>Depth jump (61cm)</li>
 </ol>
 </td>
 <td>
 <ol>
 <li>Dumbbell squat jump (30%RM)</li>
 <li>Countermovement jump</li>
 <li>Depth jump (61cm)</li>
 <li>Depth jump (46cm)</li>
 <li>Squat Jump</li>
 <li>Single leg jump</li>
 <li>Pike jump</li>
 <li>Tuck jump</li>
 </ol>
 </td>
 </tr>
 </tbody>
</table>
Strengths:
<ul>
 <li>Exercise randomization and standardized rest periods likely reduced the influence of a fixed order or fatigue.</li>
 <li>Large differences in effects sizes among <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises were observed in multiple measurements of force, which reduces the likelihood that these differences were the result of chance.</li>
 <li>Participants exhibited a wide range of body weights (69-96kg), strengthening the statistical analysis of both GRF/BW and K-JRF/BW.</li>
 <li>The exercises included in the study are commonly used in strength and conditioning programs to improve performance, increasing the applicability of study results.</li>
 <li>The inclusion of 3 different measurements (E-RFD, K-JRF and <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>) allows for a direct comparison of how these measurements may be related to one another.</li>
</ul>
Weaknesses and Limitations:
<ul>
 <li>This study included a small number of participants (6), with large variations in performance between individuals, which may decrease the statistical <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> of the study findings.</li>
 <li>Knee joint forces were estimated using an equation developed in a previous study, but more research is needed to validate the use of this equation in various populations.</li>
 <li>The study included very high-level athletes (Division I), which may reduce the generalizability of the findings to other populations.</li>
</ul>

The Brookbush Institute (BI) continues to develop and refine recommendations for strength and performance training, and specifically <a href="https://brookbushinstitute.com/article/introduction-power-training-high-velocity-training" target="_blank" rel="noopener">power training</a>. This study&#x2019;s findings suggest that human movement professionals may need to consider both eccentric rate of force development (E-RFD) and knee joint reaction forces (K-JRF) when determining intensity for <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise. The BI has <a id="integration" data-tip="1473" target="_blank" href="/glossary-term/integration" class="glossary">integrated</a> these findings into recommendations for <a href="https://brookbushinstitute.com/article/power-training-lower-body-exercises" target="_blank" rel="noopener">Power Exercise Progressions: Lower Body</a>. The BI will continue to pursue <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> practice by refining <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> exercise recommendations, using the aggregated results of all available original research.
<h3>For more information check out:</h3>
<ul>
 <li><a href="https://brookbushinstitute.com/course/power-training-lower-body-exercises" target="_blank" rel="noopener">Power (High-velocity) Training: Lower Body</a></li>
</ul>

<h3>Single Leg Box Jump Exercise</h3>
<iframe src="https://player.vimeo.com/video/156507319" frameborder="0" allowfullscreen="allowfullscreen"></iframe>
<h3>Single Leg Drop Jump</h3>
<iframe src="https://player.vimeo.com/video/157878913" frameborder="0" allowfullscreen="allowfullscreen"></iframe>
<h3>Depth Jump</h3>
<iframe src="https://player.vimeo.com/video/247907846" frameborder="0" allowfullscreen="allowfullscreen"></iframe>

Videos

<ol>
 <li>Markovic, G. (2007). Does plyometric training improve vertical jump height? A meta-analytical review. British Journal of Sports Medicine, 41, 349-355.</li>
 <li>Ebben, W.P., Blackard, D.O. and Jensen, R.L (1999). Quantification of medicine ball vertical impact forces: Estimating effective training loads. Journal of Strength and Conditioning Research, 13, 271-274.</li>
 <li>Bauer, J.J., Fuchs, R.K., Smith, G.A. and Snow, C.M. (2001). Quantifying force magnitude and loading rate from drop landings that induce osteogenesis. Journal of Applied Biomechanics, 17, 142-152.</li>
 <li><a href="https://brookbushinstitute.com/article/joint-power-absorption-ranking-plyometric-exercises" target="_blank" rel="noopener">Van Lieshout, KG., Anderson, JG., Shelburne, K.B. and Davidson, BS. (2014). Intensity rankings of plyometric exercises using joint power absorption. Clinical Biomechanics, 29, 918-922.</a></li>
 <li><a href="https://brookbushinstitute.com/article/using-time-stabilization-evaluate-plyometric-exercises" target="_blank" rel="noopener">Ebben, W.P., VanderZanden, T., Wurm, B.J. &amp; Petushek, E. (2010). Evaluating plyometric exercises using time to stabilization. Journal of Strength &amp; Conditioning Research, 24(2), 300-306</a></li>
 <li><a href="https://brookbushinstitute.com/article/emg-analysis-plyometric-intensity" target="_blank" rel="noopener">Ebben, W.P., Fauth, M.L., Garceau, L.R. and Petushek, E.J. (2011). Kinetic quantification of plyometric exercise intensity. Journal of Strength &amp; Conditioning Research, 25(12), 3288-3298</a></li>
 <li><a href="https://brookbushinstitute.com/article/emg-analysis-plyometric-intensity" target="_blank" rel="noopener">Ebben, WP., Simenz, C. and Jensen, RL. (2008). Evaluation of plyometric intensity using electromyography. Journal of Strength &amp; Conditioning Research, 22(3), 861-868</a></li>
</ol>

Wallace et al. (2010). Quantifying of Vertical Ground Reaction Forces of Plyometric Exercises

Original Citation: Wallace, BJ, Kernozek, TW, White, JM, Kline, DE, Wright, GA, Peng, HT and Huang, CF (2010). Quantification of vertical <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> of popular <a id="bilateral" data-tip="1552" target="_blank" href="/glossary-term/bilateral" class="glossary">bilateral</a> <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises. Journal of Strength and Conditioning Research, 24(1), 207-212. - <a href="https://www.ncbi.nlm.nih.gov/pubmed/19924006" target="_blank" rel="noopener">ARTICLE</a>
<h3>Why the study is relevant:</h3>
<a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> training has demonstrated efficacy for improving sports performance (1). However, relatively few studies have compared <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercises based on objective data, resulting in professionals relying on subjective rankings of intensity or anecdotal evidence when selecting or progressing exercise. This 2010 study by American researchers compared peak <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>) to create an intensity index for several common <a id="bilateral" data-tip="1552" target="_blank" href="/glossary-term/bilateral" class="glossary">bilateral</a> <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">Plyometric</a> exercises. The findings of this study suggest that peak vertical <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>) vary significantly between <a id="bilateral" data-tip="1552" target="_blank" href="/glossary-term/bilateral" class="glossary">bilateral</a> exercises (standing long jump, double jump, vertical jump, depth jump and drop jump), as well as between incremental increases in height of 30 centimeters or more.
<a href="https://brookbush.s3.us-east-2.amazonaws.com/wordpress/wp-content/uploads/2017/09/Depth-Jump-2.png" target="_blank" rel="noopener"><img src="https://brookbush.s3.us-east-2.amazonaws.com/wordpress/wp-content/uploads/2017/09/Depth-Jump-2.png" alt="Dr. Brookbush instructs an athlete on performing a depth jump. "></a>

<table>
 <tbody>
 <tr>
 <td width="40%">Study Design</td>
 <td>Randomized order, repeated-measures, comparative study</td>
 </tr>
 <tr>
 <td>Level of Evidence</td>
 <td>III Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies, and case-control studies</td>
 </tr>
 <tr>
 <td>Participant Characteristics</td>
 <td>Demographics
 <ul>
 <li>Participants: 14</li>
 <li>Age (&#xB1; standard deviation, in years): 22.5 &#xB1; 3.5</li>
 <li>Gender: Male</li>
 <li>Height: 177.1 &#xB1;5.6 cm</li>
 <li>Body Mass: 87.2 &#xB1;16.5 kg</li>
 </ul>
 Inclusion Criteria:
 <ul>
 <li>Experience performing each exercise</li>
 <li>Continuous participation in a sport-specific training program for at least 6 months prior to participating in the study</li>
 <li>Power-oriented track and field athletes in their off-season.</li>
 </ul>
 Exclusion criteria:
 N/A
 </td>
 </tr>
 <tr>
 <td>Methodology</td>
 <td>9 plyometric exercises:
 <ul>
 <li>Depth Drop (Allowed to absorb force and swing arms): 30cm, 60cm, 90cm</li>
 <li>Drop Jump (Cued to keep stiff legs and hands on hips): 30cm, 60cm, 90cm</li>
 <li>Vertical Jump</li>
 <li>Standing Long Jump</li>
 <li>2 Consecutive Jump</li>
 </ul>
 Procedure:
 <ul>
 <li>In a single session, participants were evaluated on each of the 9 <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises.</li>
 <li>Participants were instructed to abstain from rigorous physical activity for at least 24 hours prior to the session.</li>
 <li>All participants wore the same footwear, the New <a id="balance" data-tip="1190" target="_blank" href="/glossary-term/balance" class="glossary">Balance</a> running shoe, <a id="model" data-tip="1469" target="_blank" href="/glossary-term/model" class="glossary">Model</a> 629, to control for the absorption properties of different soles.</li>
 <li>A standardized, dynamic warm-up consisting of various lower-body lunges and squatting movements was performed prior to testing.</li>
 <li>Participants then rested for 5 minutes before testing began.</li>
 <li>The order in which the <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises were performed was randomized.</li>
 <li>Participants used the same starting position to jump onto the force platform for the standing long jump and the 2 consecutive jumps.</li>
 <li>Three trials were completed for each exercise.</li>
 <li>A 90-second recovery was permitted between <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises.</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Data Collection and Analysis</td>
 <td>
 <ul>
 <li>One-way repeated measures were used to <a id="assessment" data-tip="1482" target="_blank" href="/glossary-term/assessment" class="glossary">test</a> for statistically significant differences between the depth drop and drop jump and between all exercises relative to the vertical jump condition.</li>
 <li>The level of significance was set at P&lt;0.05 for all analyses.</li>
 </ul>
 </td>
 </tr>
 <tr>
 <td>Results</td>
 <td>
 <ul>
 <li>Peak vertical <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (VGRF) for the standing long jump and 2 consecutive jumps were significantly different (P&lt;0.05).</li>
 <li>Peak VGRF during depth drop and drop jumps at 30cm, 60cm and 90cm drop heights differed significantly.</li>
 <li>30cm, 60cm and 90cm drop heights were statistically different from one another within the depth drop and drop jump.</li>
 <li>The 30cm depth drop, vertical jump, 2 consecutive jumps and 60cm drop jump all resulted in a mean peak VGRF between 3-4 times body weight.</li>
 <li>The 30cm drop jump was the only exercise with a mean peak VGRF of less than 3 times body weight</li>
 <li>The standing long jump, 60cm depth drop and 90cm drop jump resulted in a mean peak VGRF between 4-5 times body weight.</li>
 <li>The 90cm depth drop had the largest mean peak VGRF, at 5.39 times body-weight</li>
 <li>Intra-class correlation coefficients for each exercise ranged from 0.65 to 0.94.</li>
 </ul>
 Plyometric Exercise - Peak Vertical <a id="ground-reaction-force" data-tip="1395" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">Ground Reaction Force</a> (Newtons/Meter)
 <ol>
 <li>30cm drop jump - 2.87 &#xB1; 0.44</li>
 <li>30cm depth drop - 3.33 &#xB1; 1.05</li>
 <li>Vertical jump - 3.34 &#xB1; 0.95</li>
 <li>2 consecutive jumps - 3.68 &#xB1; 0.82</li>
 <li>60cm drop jump - 3.82 &#xB1; 0.64</li>
 <li>Standing long jump - 4.22 &#xB1; 0.64</li>
 <li>60cm depth drop - 4.31 &#xB1; 1.33</li>
 <li>90cm drop jump - 4.93 &#xB1; 0.72</li>
 <li>90cm depth drop - 5.39 &#xB1; 1.64</li>
 </ol>
 </td>
 </tr>
 <tr>
 <td>Our Conclusions</td>
 <td>The findings of this study suggest that peak vertical ground reaction forces (GRF) vary significantly between bilateral exercises, as well as between incremental increases in height of 30cm&apos;s or more. These findings may aid human movement professionals in selecting the appropriate exercise based on the athlete&apos;s ability, progress exercise based on GRF, and determine minimum progressions for competitive play.</td>
 </tr>
 </tbody>
</table>
<a href="https://brookbush.s3.us-east-2.amazonaws.com/wordpress/wp-content/uploads/2020/07/Box-Jump-Mike.png" target="_blank" rel="noopener"><img src="https://brookbush.s3.us-east-2.amazonaws.com/wordpress/wp-content/uploads/2020/07/Box-Jump-Mike.png" alt="Box Jump"></a>

There is a growing body of research comparing <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercise intensity based on objective data. Many of these studies have demonstrated less-than-intuitive rankings that should give human movement professionals impetus to reconsider <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> exercise <a id="exercise-progression" data-tip="1182" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progressions</a> and exercise selection. This study compared <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>) of various <a id="bilateral" data-tip="1552" target="_blank" href="/glossary-term/bilateral" class="glossary">bilateral</a> lower extremity <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> exercises with various heights of drop and depth jumps. Potentially surprising findings include, vertical jump resulting in larger <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> than 30cm depth or drop jump, standing long jump resulting in similar <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> as 60cm depth or drop jumps, and depth jumps resulting in larger <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> then drop jumps (also known as &quot;shock drops&quot;) at all heights. This objective data may aid in the selection and <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progression</a> of <a id="plyometric" data-tip="1295" target="_blank" href="/glossary-term/plyometric" class="glossary">plyometric</a> activity.

This study demonstrated that increases in drop or depth jump height significantly increased <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>, as well as demonstrating that vertical jumps and long jumps result in similar <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> as 30cm and 60cm depth/drop jumps. Further, this study described these forces in terms of multiples of body weight, which may aid movement professionals in their selection of exercise, especially in a rehab setting. For example, a 30cm depth drop resulted in an average peak <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> of 3.33 times body weight, and a 36&quot; depth drops resulted in an average peak <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> of 5.39 times body weight. Findings from this study may imply the following order of intensity from lowest to highest <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> (exercise - <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> in multiples of body weight).
<ol>
 <li>30cm drop jump - 2.87 &#xB1; 0.44</li>
 <li>30cm depth drop - 3.33 &#xB1; 1.05</li>
 <li>Vertical jump - 3.34 &#xB1; 0.95</li>
 <li>2 consecutive jumps - 3.68 &#xB1; 0.82</li>
 <li>60cm drop jump - 3.82 &#xB1; 0.64</li>
 <li>Standing long jump - 4.22 &#xB1; 0.64</li>
 <li>60cm depth drop - 4.31 &#xB1; 1.33</li>
 <li>90cm drop jump - 4.93 &#xB1; 0.72</li>
 <li>90cm depth drop - 5.39 &#xB1; 1.64</li>
</ol>
Strengths:
<ul>
 <li>Randomization of exercise order and adequate rest periods (work-to-rest ratios of at least 1:5) reduced the potential influence of fatigue.</li>
 <li>The exercises included in the study are commonly used in strength and conditioning programs to improve performance, increasing the applicability of study results.</li>
 <li>Measurements of <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> were carried out using validated technology, enhancing the <a id="accuracy" data-tip="1218" target="_blank" href="/glossary-term/accuracy" class="glossary">accuracy</a> and confidence in study findings.</li>
 <li>Footwear was standardized to reduce the impact of sole thickness on <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a> measurements.</li>
</ul>
Weaknesses and Limitations:
<ul>
 <li>Exclusion criteria did not include functional screening to identify potential musculoskeletal limitations.</li>
 <li>The study only included male college athletes, which may reduce the generalizability of the findings to other populations.</li>
 <li>The long jump and vertical jump were not standardized to the athlete&apos;s ability, which may have impacted the &quot;ranking&quot; of the exercise based on <a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>.</li>
</ul>

The Brookbush Institute (BI) encourages &quot;progressions&quot; for all aspects of a program. This includes the <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progression</a> from isolated <a id="activation-technique" data-tip="1531" target="_blank" href="/glossary-term/activation-technique" class="glossary">activation techniques</a> to reactive <a id="activation-technique" data-tip="1530" target="_blank" href="/glossary-term/activation-technique" class="glossary">activation exercises</a>, the <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progression</a> of strength exercises from stable to less stable, stability/endurance training to max strength/power training, and the <a id="exercise-progression" data-tip="1184" target="_blank" href="/glossary-term/exercise-progression" class="glossary">progression</a> of intensity of plyometric/power exercises over time. This study&#x2019;s findings suggest that human movement professionals may need to consider <a id="ground-reaction-force" data-tip="1397" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">ground reaction forces</a> (<a id="ground-reaction-force" data-tip="1398" target="_blank" href="/glossary-term/ground-reaction-force" class="glossary">GRF</a>) when selecting and progressing <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> exercises. The BI has <a id="integration" data-tip="1473" target="_blank" href="/glossary-term/integration" class="glossary">integrated</a> these findings into recommendations for <a href="https://brookbushinstitute.com/article/power-training-lower-body-exercises" target="_blank" rel="noopener">Power Exercise Progressions: Lower Body</a>. The BI will continue to pursue <a id="optimal" data-tip="1571" target="_blank" href="/glossary-term/optimal" class="glossary">optimal</a> practice by refining <a id="power" data-tip="1399" target="_blank" href="/glossary-term/power" class="glossary">power</a> exercise recommendations, using the aggregated results of all available original research.
<h3>For more information check out:</h3>
<ul>
 <li><a href="https://brookbushinstitute.com/article/strength-training/power-training-lower-body-exercises/" target="_blank" rel="noopener">Power (High-velocity) Training: Lower Body</a></li>
</ul>

<h3>Hop Down to Stabilization</h3>
<iframe src="https://player.vimeo.com/video/82858557" frameborder="0" allowfullscreen="allowfullscreen"></iframe>
<h3>Lateral Hop to Single-leg Vertical to Balance</h3>
<iframe src="https://player.vimeo.com/video/156491756" frameborder="0" allowfullscreen="allowfullscreen"></iframe>
<h3>Depth Jumps</h3>
<iframe src="https://player.vimeo.com/video/247907846" frameborder="0" allowfullscreen="allowfullscreen"></iframe>

<ol>
 <li>Markovic, G. (2007). Does plyometric training improve vertical jump height? A meta-analytical review. British Journal of Sports Medicine, 41, 349-355.</li>
 <li>Potach, DH. and Chu, DA. (2008). Plyometric Training. In: Essentials of Strength Training &amp; Conditioning, Baechle, TR and Earle, RW, eds. Champaign, IL: Human Kinetics, 413-456.</li>
 <li>Tongen, A., &amp; Wunderlich, R. E. (2010). Biomechanics of running and walking. Mathematics and Sports, 43.
 Ford, KR, Myer, GD. and Hewett, TE. (2003). Valgus knee motion during landing in high school female and male basketball players. Medicine Science Sports &amp; Exercise, 35, 1745-1750.
 </li>
 <li>Kernozek, TW, Torry, MR, Van Hoof, H, Cowley, H. and Tanner, S. (2005). Gender differences in frontal and sagittal plane biomechanics during drop landings. Medicine Sports Science &amp; Exercise, 37, 1003-1012.</li>
 <li>Jensen, RL. and Ebben, WP. (2007). Quantifying plyometric exercise intensity via rate of force development, knee joint, and ground reaction forces. Journal of Strength and Conditioning Research, 21(3), 763-767</li>
 <li>Van Lieshout, KG., Anderson, JG., Shelburne, K.B. and Davidson, BS. (2014). Intensity rankings of plyometric exercises using joint power absorption. Clinical Biomechanics, 29, 918-922</li>
 <li>Ebben, WP., Simenz, C. and Jensen, RL. (2008). Evaluation of plyometric intensity using electromyography. Journal of Strength &amp; Conditioning Research, 22(3), 861-868</li>
 <li>Ebben, W.P., VanderZanden, T., Wurm, B.J. &amp; Petushek, E. (2010). Evaluating plyometric exercises using time to stabilization. Journal of Strength &amp; Conditioning Research, 24(2), 300-306</li>
 <li>Ebben, W.P., Fauth, M.L., Garceau, L.R. and Petushek, E.J. (2011). Kinetic quantification of plyometric exercise intensity. Journal of Strength &amp; Conditioning Research, 25(12), 3288-3298.</li>
</ol>

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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