Short vs. Long Rest Periods Between Sets in Hypertrophic Resistance Training

Research Review: Short vs. Long Rest Periods Between the Sets in Hypertrophic Resistance Training: Influence on Muscle Strength, Size, and Hormonal Adaptations in Trained Men.

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: Ahtiainen, J.P., Pakarinen, A., Alen, M., 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 and Conditioning Research, 19 (3), 572-582. -- ABSTRACT

Why the Study is Relevant: Inter-set rest intervals of 30 seconds to 5 minutes have been recommended to promote hypertrophy based on a variety of rationales and physiological benefits. This 2005 study compared the effects of 2 -minute and 5 -minute rest intervals on long-term physiological adaptions, such as hormonal changes, body composition and muscle cross-sectional area (CSA). The resulting lower-intensity short rest interval and higher-intensity long rest interval programs induced similar hormonal, nervous-system, and muscular responses. This may imply that the duration of inter-set rest may not influence the magnitude of hypertrophy adaptations when intensity is sufficient.

Study Summary

Caption: Horizontal Pull-up

How This Study is Important:

This study provides evidence comparing physiological changes during a 6-month hypertrophy program using two inter-set rest intervals (2 -minutes vs 5 -minutes). When long-term changes in hormonal response, body composition and muscle cross-sectional area (CSA) were measured over-time, no significant difference was noted. This may imply that inter-set rest intervals may have less influence on hypertrophy, when intensity/load is adjusted accordingly. Further, this study may suggest that the acute hormonal and performance changes correlated with longer or shorter inter-set rest intervals, may not have an impact on long-term hypertrophy gains.

How the Findings Apply to Practice:

Hormonal and muscular responses did not differ significantly between the two inter-set rest intervals. Human movement professionals can recommend high-intensity loads with longer inter-set rest intervals (5 -minutes); or lower-intensity loads with shorter intervals (2 -minutes) to promote muscle hypertrophy. These findings match the recommendations often proposed in periodized models of training.

Strengths and Weaknesses:

This study had many methodological strengths, including:

• The crossover design reduced the influence of confounding variables including individual ability, dietary measures, and sleep habits.
• The weight chosen for the 10-repetition sets was based on each participant's ability level, the participants were instructed on proper technique and were familiarized with each exercise, and all exercises were performed on the same equipment for lower body training throughout the 6-month study, increasing internal validity and replicability.
• The study investigated several commonly researched variables (CSA, hormone response, EMG, strength, etc.), allowing for direct comparison within the studies cohort.
• This study was fairly long (6-months) relative to the body of research in strength training, allowing for significant morphological changes to be compared.

Weaknesses that should be noted:

• Only 6 of the 13 participants kept consistent training logs, limiting the reliability of findings and accuracy of practical implications.
• Twenty initial participants were selected, but 7 discontinued the study due to injury; limiting the power of the findings (and perhaps prompting concerns of risk of injury with the program used).
• The authors noted that the participants may have been over-trained. This can negatively influence strength, stability and neuromuscular adaptations (8).
• While all lower body exercises remained consistent between participants, a precise protocol was not mandated, limiting replicability.

How does it relate to Brookbush Institute Content?

The Brookbush Institute (BI) continues to refine protocols for the selection of acute variables during performance and rehabilitation programs. Consideration of all available research is essential to providing the most accurate protocols possible. Studies like the one reviewed here, provide essential data for refining acute variable protocols. This study supports the use of shorter inter-set rest intervals for lower intensity exercise, and longer inter-set rest intervals for higher intensity exercise, as is recommended by most periodized programs (including the BI). Future research should compare inter-set rest intervals less than 2 minutes in length.

Sample videos of Lower Body Strength Training below:

Deadlift with Anterior to Posterior Pull

Lateral Lunge with Front Rack Resistance:

Front Squat:

Bibliography:

1. Baechle, T.R., & Earle, R.W. (2008). Essentials of Strength Training and Conditioning (3rd ed.). Champaing, IL; Human Kinetics.
2. Kraemer, W.J., Marchitelli, L., Gordon, S.E., Harmon, E., Dziados, J.E., Mello, R., Frykman, P., Mcurry, D. & Fleck, S.J. (1990). Hormonal and growth factor responses to heavy resistance exercise protocols. Journal of Applied Physiology 69, 1442-1450.
3. Kraemer, W.J., Adams, K., Cafarelli, E., Dudley, G.A., Dooly, C., Feigenbaum, M.S., Fleck, S.J., … Triplett-McBride, T. (2002). American College of Sports Medicine position stand: Progression models in resistance training for healthy adults. Medical Science in Sports and Exercise, 34 (2), 364-380.
4. Fleck, S.J. & Kraemer, W.J. (1997). Designing resistance training programs (2nd ed.). Chapaign, IL; Human Kinetics.
5. Durnin, J.V. & Rahaman, M.M. (1967). The assessment of the amount of fat in the human body from measurement of skinfold. British Journal of Nutrition, 21 (3), 681-689.
6. Filho, J.C.J., Gobbi, L.T.B., Gurjao, A.L.D., Concalves, R., Prado, A.K.G., & 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 & Medicine, 12 (1), 138-143.
7. Hernanez-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. Sparto, P.J., Parnianpour, M., Reinsel, T.E., & Simon, S. (1997). The effect of fatigue on multijoint kinematics, coordination, and postural stability during a repetitive lifting test. Journal of Orthopaedic & Sports Physical Therapy, 25 (1), 3-12.
9. Hernandez-Davo, J., Solana, R., Marin, J., Fernandez-Fernandez, J., and Ramon, M. (2016). Rest interval required for power training with power load in the bench press throw exercise. Journal of Strength and Conditioning Research, 30(5), 1265-1274.
10. 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
11. 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
12. 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 .
13. 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

© 2018 Brent Brookbush

Questions, comments, and criticisms are welcomed and encouraged -