The sum of studies that found stretching between sets does not enhance muscle growth is greater than those that found it beneficial. More research needs to be conducted to determine if stretching between sets will enhance muscle growth, but the verdict now is that stretching between sets is not meaningful.
SUMMARY OF INTRA SET STRETCHING
- Stretching between sets for 45 seconds resulted in a 32.8% decrease in training volume. Furthermore, no increases in strength gains or muscle growth were observed.
Among the factors that stimulate muscle growth are training volume, training intensity, rest period duration, etc. Several articles on Evidence Based Muscle have been written about long and short rest periods. Training sessions with short rest periods have resulted in greater muscle damage, lower training volume, and lower protein synthesis and muscle growth.
There has been a lot of excitement about the various forms of stretching-mediated hypertrophy. You may have read the article on Evidence-Based Muscle about stretching the calves for an hour a day increases muscle growth. Another recent article found that performing biceps curls emphasizing eccentric contractions (i.e., lengthening position) resulted in greater muscle growth.
STRETCHED OUT! WILL STRETCHING RESULT IN GREATER MUSCLE GAINS?
Stretches involving lengthening the muscle between sets have been suggested to increase anabolic signaling pathways, which can lead to greater muscle growth. (Schoenfeld et al., 2022; TATSUMI, 2010; Wisdom et al., 2015) Furthermore, full range of motion training results in greater muscle growth than partial reps. (Schoenfeld & Grgic, 2020)
An increased range of motion emphasizing eccentric contractions is beneficial for muscle hypertrophy. (Hedayatpour & Falla, 2015) Isometric contractions in which the muscle remains neutral are less conducive to muscle growth. (Neves et al., 2019)
Some studies have found that stretching between sets can increase muscle growth (Evangelista et al., 2019; Van Every et al., 2022); however, others have found no beneficial effects for muscle hypertrophy. (Souza et al., 2013; T. Wadhi et al., 2022)
The differences in types of stretching protocols may be why the research is so confusing. The research studies used different stretching periods (i.e., hold relax duration or period of time muscle was lengthened), differences in ranges of motion intensity (i.e., how painful was the active stretch), and the types of protocols utilized in the study (i.e., the muscle being trained was stretched or the opposite muscle).
NEW STUDY ON STRETCHING BETWEEN SETS
Most studies that have found beneficial effects for stretching between sets have used stretch durations of 30 seconds. Researchers decided to re-examine the effects of stretching between sets. Researchers divided 22 men and women into 2 groups:
1.) Traditional strength training with no stretching between sets (i.e., rested 2 minutes between sets).
2.) Strength training with stretching between sets. The stretching protocol consisted of stretching the opposite muscle group trained for 45 seconds and resting for 45 seconds. A trainer stretched the subjects to a pain scale between 7-9 on a scale of 10.
The resistance training program focused on the biceps and triceps. The program was a high-volume resistance training program that involved training the biceps and triceps twice per week. The biceps exercise consisted of 16 sets per week, and the triceps exercise consisted of 19 sets per week.
The study lasted 8 weeks. The biceps exercises, directly and indirectly, emphasized biceps activation, such as bicep curls, lat pulldowns, supine cable row, and supine grip lat pulldowns. Triceps exercises were overhead triceps extension, bench press, machine bench press, and close grip bench press. The subjects kept track of their protein, calories, and macros to ensure no differences.
At the end of the study, the group that stretched had a drop in volume by 32.8%. Despite the drop in volume from stretching, there was no difference in strength or muscle mass between the groups. Surprisingly, despite the stretching group performing less volume, muscle strength, and muscle growth were not impaired. (Borsetti Businari et al., 2023) Another interesting finding was that strength increased without any real muscle growth in both groups.
The researchers suggested that 8 weeks may not have been enough time to see changes in muscle growth from stretching. They also noted that the participants’ volume was higher than what the subjects performed in their normal training.
The subject’s weekly training sets (i.e., direct and indirect arm exercises) for the biceps average was 29.5 sets and 26.6 sets for the triceps. The sets per week averaged 46 sets per week for both biceps and triceps. The researchers acknowledged that this may have been too many sets which resulted in sub-par muscle hypertrophy.
WHAT TO DO WHILE RESTING BETWEEN SETS?
Based on the research, you need to stretch the muscle for a long time to see muscle growth. The earlier study mentioned above found that passive stretching increased calf growth when the calves were stretched for an hour a day. Ballistic stretching, in which there are short bursts of muscle lengthening, is less effective than having the muscle lengthened for prolonged periods. (Warneke et al., 2022)
The sum of studies that found stretching between sets does not enhance muscle growth (Borsetti Businari et al., 2023; Nakamura et al., 2021; Souza et al., 2013; Tanuj Wadhi et al., 2022) is greater than those that found it beneficial (Evangelista et al., 2019; Van Every et al., 2022). More research needs to be conducted to determine if stretching between sets will enhance muscle growth, but as of right now, it does not seem meaningful.
Borsetti Businari, G., Brigatto, F., Camargo, J., Soares, E., Braz, T., Batista, D., Col, L., Dias, W., Rosolem, J., Prestes, J., Marchetti, P., Lopes, C., & Garcia, M. (2023). Chronic Effects of Inter-Set Static Stretching on Morphofunctional Outcomes in Recreationally Resistance-Trained Male and Female. Research quarterly for exercise and sport, 1, 1-14.
Evangelista, A. L., De Souza, E. O., Moreira, D. C. B., Alonso, A. C., Teixeira, C. V. S., Wadhi, T., Rauch, J., Bocalini, D. S., Pereira, P. E. A., & Greve, J. M. D. (2019). Interset Stretching vs. Traditional Strength Training: Effects on Muscle Strength and Size in Untrained Individuals. J Strength Cond Res, 33 Suppl 1, S159-s166. https://doi.org/10.1519/jsc.0000000000003036
Hedayatpour, N., & Falla, D. (2015). Physiological and Neural Adaptations to Eccentric Exercise: Mechanisms and Considerations for Training. BioMed research international, 2015, 193741-193741. https://doi.org/10.1155/2015/193741
Nakamura, M., Ikezu, H., Sato, S., Yahata, K., Kiyono, R., Yoshida, R., Takeuchi, K., & Nunes, J. P. (2021). Effects of Adding Inter-Set Static Stretching to Flywheel Resistance Training on Flexibility, Muscular Strength, and Regional Hypertrophy in Young Men. Int J Environ Res Public Health, 18(7). https://doi.org/10.3390/ijerph18073770
Neves, R. V. P., Rosa, T. S., Souza, M. K., Oliveira, A. J. C., Gomes, G. N. S., Brixi, B., Souza, L. H. R., Deus, L. A., Simões, H. G., Stone, W. J., Prestes, J., & Moraes, M. R. (2019). Dynamic, Not Isometric Resistance Training Improves Muscle Inflammation, Oxidative Stress and Hypertrophy in Rats [Original Research]. Frontiers in Physiology, 10. https://doi.org/10.3389/fphys.2019.00004
Schoenfeld, B. J., & Grgic, J. (2020). Effects of range of motion on muscle development during resistance training interventions: A systematic review. SAGE Open Medicine, 8, 2050312120901559-2050312120901559. https://doi.org/10.1177/2050312120901559
Schoenfeld, B. J., Wackerhage, H., & De Souza, E. (2022). Inter-set stretch: A potential time-efficient strategy for enhancing skeletal muscle adaptations. Front Sports Act Living, 4, 1035190. https://doi.org/10.3389/fspor.2022.1035190
Souza, A. C., Bentes, C. M., de Salles, B. F., Reis, V. M., Alves, J. V., Miranda, H., & Novaes Jda, S. (2013). Influence of inter-set stretching on strength, flexibility and hormonal adaptations. J Hum Kinet, 36, 127-135. https://doi.org/10.2478/hukin-2013-0013
TATSUMI, R. (2010). Mechano-biology of skeletal muscle hypertrophy and regeneration: Possible mechanism of stretch-induced activation of resident myogenic stem cells. Animal Science Journal, 81(1), 11-20. https://doi.org/https://doi.org/10.1111/j.1740-0929.2009.00712.x
Van Every, D. W., Coleman, M., Rosa, A., Zambrano, H., Plotkin, D., Torres, X., Mercado, M., De Souza, E. O., Alto, A., Oberlin, D. J., Vigotsky, A. D., & Schoenfeld, B. J. (2022). Loaded inter-set stretch may selectively enhance muscular adaptations of the plantar flexors. PLoS One, 17(9), e0273451. https://doi.org/10.1371/journal.pone.0273451
Wadhi, T., Barakat, C., Evangelista, A. L., Pearson, J. R., Anand, A. S., Morrison, T. E., O’Sullivan, J., Walters, J., & De Souza, E. O. (2022). Loaded Inter-set Stretching for Muscular Adaptations in Trained Males: Is the Hype Real? International journal of sports medicine, 43(02), 168-176.
Wadhi, T., Barakat, C., Evangelista, A. L., Pearson, J. R., Anand, A. S., Morrison, T. E. A., O’Sullivan, J., Walters, J., & Souza, E. O. (2022). Loaded Inter-set Stretching for Muscular Adaptations in Trained Males: Is the Hype Real? Int J Sports Med, 43(2), 168-176. https://doi.org/10.1055/a-1529-6281
Warneke, K., Freund, P. A., & Schiemann, S. (2022). Long-Lasting Stretching Induces Muscle Hypertrophy: A Meta-Analysis of Animal Studies. Journal of Science in Sport and Exercise. https://doi.org/10.1007/s42978-022-00191-z
Wisdom, K. M., Delp, S. L., & Kuhl, E. (2015). Use it or lose it: multiscale skeletal muscle adaptation to mechanical stimuli. Biomechanics and Modeling in Mechanobiology, 14(2), 195-215. https://doi.org/10.1007/s10237-014-0607-3