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Tuesday, June 6, 2023

The Effect of Different Rest Intervals Between Sets on Volume Components and Strength Gains

Brent Brookbush

Brent Brookbush

DPT, PT, MS, CPT, HMS, IMT

Research Review: The Effect of Different Rest Intervals Between Sets on Volume Components and Strength Gains.

By David Boettcher MSc, BA, NASM CPT, PES, CES & NPTI

Edited by Brent Brookbush DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: Willardson, M., & Burkett, L.N. (2008). The effect of different rest intervals between sets on volume components and strength gains. Journal of Strength and Conditioning Research, 22 (1), 146-152. - ABSTRACT

Why the Study is Relevant: Recommendations on inter-set rest interval length for improving muscular strength vary between strength training organizations (1 - 3). This 2008 study compared changes in strength among 15 resistance-trained participants when using 2- or 4- minute rest intervals. Strength adaptations were similar in both groups, despite greater volume performed in the 4-minute rest interval group. This suggests that human movement professionals may recommend 2-minute or 4-minute inter-set rest intervals for promoting optimal strength adaptations.

Dr. Brookbush instruct Laura DeAngelis on proper form for a Bench Press
Caption: Dr. Brookbush instruct Laura DeAngelis on proper form for a Bench Press

Bench Press

Study Summary

Study DesignRandomized Crossover Design
Level of EvidenceIB Evidence from at least one randomized controlled trial
Subject Characteristics

Demographics

  • Gender: male
  • Number of participants: 15
  • Age: 22.75 + 4.56 for 4-minute group (8 participants)
  • Age: 20.71 + 1.38 for 2-minute group (7 participants)

Inclusion Criteria:

  • Former high school and collegiate football players
  • Performed squat exercises consistently for at least 4 years as part of a strength training regimen
  • Completed 90% of the scheduled workouts

Exclusion Criteria:

  • No strength training for hip, knee, or trunk extensors.
  • Limited resistance training experience.
Methodology
  • A squat testing session established a 1-repetition max (RM) for all participants prior to the 12 week intervention.
  • Three mesocycles, each lasting 4 weeks, were completed for a 12-week total.
  • Participants trained the same each week at the university strength facility.
  • Participants were randomly assigned to either a 2-minute or 4-minute rest interval group.
  • All participants performed heavy and light squat routines separated by a 72-hour interval each week.
  • All heavy squat workouts began with two warm-up sets of 10 repetitions, with 50% and then 75% of each participants’ 1-RM.
    • All working sets for the heavy workout were performed at 70-90% of 1-RM for a pre-determined amount of repetitions.

  • All light squat workouts began with one warm-up set of 10 repetitions at 50% of 1-RM.
    • All working sets for the light workout were performed with 60% of 1-RM for eight repetitions.

  • All sets, loads and repetitions for each participant were recorded after each workout.
  • Upon completing the 12-week intervention, all participants performed a final 1-RM squat testing session.
Data Collection and Analysis
  • Independent t-tests compared the differences in age, height, and body mass between groups.
  • Squat strength gains and workload volume were compared between the two groups post-intervention.
  • The total volume per workout was calculated as the total number of sets multiplied by the mean load and mean number of repetitions during each set
  • A two-by-four repeated ANOVA compared strength scores within- and between subjects.
  • Significance was set to a p value of 0.05
  • Post-intervention 1-RM squat results were compared with a Bonferroni adjustment.
Outcome Measures
  1. 1-RM post 12-week intervention
  2. Load, repetition, intensity, and volume of each mesocycle for each group.
Results
  1. No statistically significant changes in 1RM (p=.47)
  2. The 4-minute rest-interval group demonstrated significantly higher total volumes for each heavy workout (p=0.02 – 0.04)
  3. The mean squat intensity level (%1RM) for both groups was nearly equal for all mesocycles (p=0.69-0.76)
  4. Squat strength gains were not significantly different between the 2-minute and 4-minute groups (p< 0.05)
Our ConclusionsBoth 2- and 4-minute inter-set rest intervals are beneficial for increasing strength. Human movement professionals may use either when structuring a resistance training program with a goal of increased strength.
Researchers' Conclusions

Rest intervals of 2- or 4-minutes can elicit similar strength gains in the squat exercise in experienced resistance trainers. Inter-set rest intervals can be altered according to age, training experience and exercise selection. Longer rest intervals may be beneficial for novice participants, and shorter periods for experienced lifters.

Nicholas Rolnick performs a barbell front squat.

How This Study Contributes to the Body of Research:

This study compared the changes in squat 1RM after a 12-week resistance training program using either 2- or 4-minute inter-set rest intervals. Studies have demonstrated that volume and adaptations may be affected by inter-set rest intervals of less than 2 minutes, and some studies have demonstrated that volume may be affected with longer rest intervals (5-14). This study adds to a growing body of evidence demonstrating that inter-set rest-intervals longer than 2 minutes may have no additional benefit for strength adaptations (6, 13, 14). This study adds important data regarding the interpretation of inter-set rest interval research, as strength adaptation were similar with a 2 minute inter-set rest interval, despite a 4-minute rest interval leading to greater total workloads.

How the Findings Apply to Practice:

The findings suggest that 2- and 4- minute inter-set rest intervals do not alter strength gains over the course of an undulating 12-week exercise program. This implies that human movement professionals may recommend either 2- or 4-minute rest intervals for strength adaptations. This allows flexibility in programming that may include shorter rest intervals for conditioned athletes, circuit training which may increase the length of time between sets for similar muscle groups, or increased rest between sets for less conditioned individuals.

  • Strengths
    • The crossover design reduced the influence of confounding variables, including individual ability.
    • The weights were individualized based on the participant’s strength levels at the start of the macrocycle, increasing internal validity and replicability.
    • This study’s periodized program and exercise selection allows for replicability by human movement professionals and applicability in various training and rehabilitation settings.
  • Weakness and limitations
    • The participants had at least 4-years of resistance training experience, which may decrease the generalizability of the findings.
    • The participants were regularly contacted via phone to self-report compliance; without outside verification, it is uncertain if participants were compliant.
    • Training experience was self-reported, which may decrease the validity of the population included in this study.

How Does It Relate to Brookbush Institute Content?

The Brookbush Institute (BI) continues to refine optimal acute variable selection for program design. Research studies such as this, add 3rd party objective data to client outcomes and the experience of the professional staff at the BI. This study supports the use of both 2- and 4-minute inter-set rest periods to promote strength changes. This is similar to BI recommendations for human movement professionals developing a strength training protocol. To increase the generalization of these training protocols, future research should compare the inter-set rest intervals and volume which are necessary to induce strength adaptations in both upper and lower body muscular. In addition, these results should be compared to similar programming with less experienced individuals.

Sample videos from the Brookbush Institute Video Library (Variations of a Squat):

Squat Form and Modifications

Back Squat

Front Squat

Squat to Row

Bibliography:

  1. Baechle, T.R., & Earle, R.W. (2008). Essentials of Strength Training and Conditioning (3rd ed.). Champaing, IL; Human Kinetics.
  2. American College of Sports Medicine. (2009). Position stand: Progression models in resistance training for healthy adults. Medical Science in Sports and Exercise, 41(3 ), 687-708.
  3. Sutton, B. (2017). NASM essentials of personal fitness training: 6th Edition. Lippincott Williams & Wilkins.
  4. Fleck, S.J. & Kraemer, W.J. (1997). Designing resistance training programs (2nd ed.). Champaign, IL; Human Kinetics.
  5. Jambassi Filho, J., Gobbi, L., Gurjao, A., Goncalves, R., Prado, Alexandre, and Gobbi, S. (2013). Effect of different rest intervals, between sets, on muscle performance during leg press exercise, in trained older women. Journal of Sports Science and Medicine, (12), 138-143.
  6. Fink, J., Schoenfeld, B., Kikuchi, N., & Nazakato, K. Acute and long-term responses to different rest intervals in low-load resistance training. International Journal of Sports Medicine. Int J Sports Med. 2017; 38(02): 118-124.
  7. Hernandez-Davo, J., Ruiz, J., & Sabido, R. (2017). Influence of strength level on the rest interval required during an upper-body power training session. Journal of Strength and Conditioning Research, 31(2), 339-347
  8. Senna G, Willardson JM, Salles BF, Scudese E, Carneiro F, Palma A, Simão R. The effect of rest interval length on multi and single-joint exercise performance and perceived exertion. J Str Cond Res. Nov 2011; 25(11): 3157-3162
  9. Schoenfeld, B.J., Pope, Z.K., Benik, F.M., Hester, G.M., Sellers, J., Nooner, J.L., Schnaiter, J.A., Bond-Williams, K.E., Carter, A.S., Ross, C.L. and Just, B.L. Longer interset rest periods enhance muscle strength and hypertrophy in resistance-trained men. J Str Cond Res. July 2016; 30(7): 1805-1812.
  10. Humberto, M., Simao, R., Moreira, L.M., de Souza, R.A., de Souza, J.A., de Salles, B.F., & Willardson, J.M. (2009). Effect of rest interval length on the volume completed during upper body resistance exercise. Journal of Sports Science and Medicine, 8 (3), 388-392.
  11. Kraemer, W.J., Noble, B.J., Clark, M.J., & Culver, B.W. (1987). Physiological responses to heavy-resistance exercise with very short rest periods. International Journal of Sports Medicine, 8 (4), 247-252.
  12. Pincivero, D.M., Lephart, S.M., & Karunakara, R.G. (1997). Effects of rest interval on isokinetic strength and functional performance after short-term high intensity training. British Journal of Medicine, 31 (3 ), 229-234.
  13. Ahtiainen, J.P., Pakarinen, A.A., Kraemer, W.J., & Hakkinen, K. (2005). Short vs. long rest periods between the sets in hypertrophic resistance training: Influence on muscle strength, size, and hormonal adaptations in trained men. Journal of Strength Conditioning Research, 19 (3), 572-582.
  14. Richmond, S.R. & Godard, M.P. (2004). The effects of rest periods between sets to failure using the bench press in recreationally trained men. Journal of Strength and Conditioning Research, 18(4), 846-859.

© 2017 Brent Brookbush

Questions, comments, and criticisms are welcomed and encouraged -

Related Articles:

Acute and Long-term Responses to Different Inter-set Rest Periods in Low-load Resistance Training

Effect of Back Squat Depth on Lower Body Post-activation Potentiation

Effect of Different Inter-set Rest Intervals on Muscle Performance During Leg Press Exercise in Trained Older Women

Effect of Rest Interval Length Between Sets on Total Load Lifted and Blood Lactate Response During Total-Body Resistance Exercise Session

Effects of Integrated vs Isolated Training on Performance and Neuromuscular Control

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