The Rationale for More Reps Per Set for Muscle Growth

A common question in training is whether low, medium, or high reps are best for maximizing hypertrophy. A survey of 127 competitive bodybuilders revealed that most trained within the seven- to 12-rep range. (1) This doesn’t necessarily mean this range is optimal for everyone. So, what rep range is best for muscle growth? 

The House of Hypertrophy tackled this question by referencing five recent meta-analyses that compared high-load and low-load training for muscle hypertrophy. 

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Optimal Rep Range

Research shows that training close to failure consistently leads to comparable muscle growth across various loads. A meta-analysis comparing high, moderate, and low loads found no significant differences in hypertrophy. High and low loads resulted in similar gains in lean mass, overall muscle size, and muscle fiber size. (2)

Most studies reviewed identified an ideal rep range between six and 35 repetitions, with the majority using a standard lifting tempo of one to two seconds for the concentric and eccentric. Slower rep speeds, therefore, don’t appear to offer additional benefits within this range.

For example, a study published in the European Journal of Applied Physiology found that performing six to 10 reps with an exaggeratedly slow tempo — 10 seconds for lifting and four for lowering — was less effective for building muscle. (3)

In summary, whether training with heavy or light loads, a moderate rep range with a normal lifting tempo is the most efficient approach for muscle growth.

Studies’ Concerns

Across five meta-analyses, certain studies focused on untrained individuals, raising the question of whether results differ for trained individuals following a complete program. Fortunately, two studies specifically examined trained participants, each performing three sets per exercise.

One group worked in the eight to 12-rep range to failure, while the other trained with 20 to 35 reps to failure. (4)(5) The findings revealed similar muscle growth in both groups, further supporting that hypertrophy can occur effectively across a wide range of repetitions.

High & Low Reps On Muscle Twitch Fibers

Research indicates that performing between six and 35 reps can lead to comparable muscle growth. Does the type of growth differ depending on the rep range?

Some argue that high-rep training targets slow-twitch muscle fibers, while low-rep training focuses on fast-twitch fibers. Early studies supported this idea, though they lacked consistency in key variables like the number of sets, rest intervals, and rep technique. (6)

A recent meta-analysis examined this topic and found that slow-twitch and fast-twitch fibers can grow similarly across a broad range of rep schemes. (7) Higher loads tend to activate both fiber types more readily, while lower loads may initially engage only slow-twitch fibers. Fast-twitch fibers are recruited as fatigue sets in and reps approach failure.

How Heavy Can You Lift? 

To determine if muscle growth is possible with fewer than six reps, assessing whether training at one’s one-rep max (1RM) can effectively stimulate hypertrophy is essential. Four studies investigated this question. (8)(9)(10)(11)

In these studies, one group performed three to four sets of eight to 12 reps, while the other group attempted their 1RM up to five times per session. The results showed significant muscle growth in the eight to 12 rep range, whereas training at 1RM led to little or no hypertrophy.

Other research suggests that training in the two-to-four rep range shows some muscle growth potential. (12) However, many of these studies didn’t standardize factors such as the number of sets or rest intervals, leaving room for variability. Based on the broader body of evidence, relying solely on the two-to-four rep range for hypertrophy isn’t recommended.

How High Many Reps? 

Performing over 35 repetitions at 30% of your one-rep max (1RM) can produce hypertrophy comparable to completing eight repetitions at 80% of your 1RM. (13) Another study observed trained individuals performing three to five sets to failure, using varying 1RM intensities across different groups:

• 20% 1RM — 64 reps
• 40% 1RM — 30 reps
• 60% 1RM — 17 reps
• 80% 1RM — 12 reps

Groups in the 40-80% range achieved comparable levels of hypertrophy, while the 20% group also experienced muscle growth, though to a lesser extent than the other conditions. (14)

Fatigue

A 2021 study suggests higher reps can lead to more significant muscle damage and longer recovery times than lower repetitions. (15) Higher reps can still play a valuable role in a well-rounded training program. Studies indicate higher repetitions can be as effective as lower repetitions when adjusting rest intervals. (16)(17)

Training To Failure

Leaving reps in reserve can result in hypertrophy gains similar to training to failure when performing fewer reps and heavier loads. However, for higher-rep sets, reaching failure may be necessary to maximize muscle growth. (18)

Research shows that training far from failure, especially with lighter loads, tends to produce less hypertrophy than training closer to failure. (19)(20) Stopping just a few reps short of failure with lighter loads is as effective as pushing to failure. (21)

The House of Hypertrophy recommends incorporating varied rep ranges into training to overcome plateaus, provided nutrition and other training fundamentals are in place.

References

1. Hackett, D. A., Johnson, N. A., & Chow, C. M. (2013). Training practices and ergogenic aids used by male bodybuilders. Journal of strength and conditioning research, 27(6), 1609–1617. https://doi.org/10.1519/JSC.0b013e318271272a
2. Lopez, P., Radaelli, R., Taaffe, D. R., Newton, R. U., Galvão, D. A., Trajano, G. S., Teodoro, J. L., Kraemer, W. J., Häkkinen, K., & Pinto, R. S. (2021). Resistance Training Load Effects on Muscle Hypertrophy and Strength Gain: Systematic Review and Network Meta-analysis. Medicine and science in sports and exercise, 53(6), 1206–1216. https://doi.org/10.1249/MSS.0000000000002585 
3. Schuenke, M. D., Herman, J. R., Gliders, R. M., Hagerman, F. C., Hikida, R. S., Rana, S. R., Ragg, K. E., & Staron, R. S. (2012). Early-phase muscular adaptations in response to slow-speed versus traditional resistance-training regimens. European journal of applied physiology, 112(10), 3585–3595. https://doi.org/10.1007/s00421-012-2339-3 
4. Schoenfeld, B. J., Peterson, M. D., Ogborn, D., Contreras, B., & Sonmez, G. T. (2015). Effects of Low- vs. High-Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men. Journal of strength and conditioning research, 29(10), 2954–2963. https://doi.org/10.1519/JSC.0000000000000958
5. Morton, R. W., Oikawa, S. Y., Wavell, C. G., Mazara, N., McGlory, C., Quadrilatero, J., Baechler, B. L., Baker, S. K., & Phillips, S. M. (2016). Neither load nor systemic hormones determine resistance training-mediated hypertrophy or strength gains in resistance-trained young men. Journal of applied physiology (Bethesda, Md. : 1985), 121(1), 129–138. https://doi.org/10.1152/japplphysiol.00154.2016 
6. Vinogradova, O. L., Popov, D. V., Netreba, A. I., Tsvirkun, D. V., Kurochkina, N. S., Bachinin, A. V., . . . Orlov, O. I. (2013). Optimization of training: New developments in safe strength training. Human Physiology, 39(5), 511–523. https://doi.org/10.1134/s0362119713050162 
7. Morton, R. W., Sonne, M. W., Farias Zuniga, A., Mohammad, I. Y. Z., Jones, A., McGlory, C., Keir, P. J., Potvin, J. R., & Phillips, S. M. (2019). Muscle fibre activation is unaffected by load and repetition duration when resistance exercise is performed to task failure. The Journal of physiology, 597(17), 4601–4613. https://doi.org/10.1113/JP278056
8. Mattocks, K. T., Buckner, S. L., Jessee, M. B., Dankel, S. J., Mouser, J. G., & Loenneke, J. P. (2017). Practicing the Test Produces Strength Equivalent to Higher Volume Training. Medicine and science in sports and exercise, 49(9), 1945–1954. https://doi.org/10.1249/MSS.0000000000001300 
9. Buckner, S. L., Yitzchaki, N., Kataoka, R., Vasenina, E., Zhu, W. G., Kuehne, T. E., & Loenneke, J. P. (2021). Do exercise-induced increases in muscle size contribute to strength in resistance-trained individuals?. Clinical physiology and functional imaging, 41(4), 326–333. https://doi.org/10.1111/cpf.12699 
10. Dankel, S. J., Counts, B. R., Barnett, B. E., Buckner, S. L., Abe, T., & Loenneke, J. P. (2017). Muscle adaptations following 21 consecutive days of strength test familiarization compared with traditional training. Muscle & nerve, 56(2), 307–314. https://doi.org/10.1002/mus.25488
11. Dankel, S. J., Bell, Z. W., Spitz, R. W., Wong, V., Viana, R. B., Chatakondi, R. N., Buckner, S. L., Jessee, M. B., Mattocks, K. T., Mouser, J. G., Abe, T., & Loenneke, J. P. (2020). Assessing differential responders and mean changes in muscle size, strength, and the crossover effect to 2 distinct resistance training protocols. Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme, 45(5), 463–470. https://doi.org/10.1139/apnm-2019-0470
12. Schoenfeld, B. J., Contreras, B., Vigotsky, A. D., & Peterson, M. (2016). Differential Effects of Heavy Versus Moderate Loads on Measures of Strength and Hypertrophy in Resistance-Trained Men. Journal of sports science & medicine, 15(4), 715–722.
13. Ozaki, H., Kubota, A., Natsume, T., Loenneke, J. P., Abe, T., Machida, S., & Naito, H. (2018). Effects of drop sets with resistance training on increases in muscle CSA, strength, and endurance: a pilot study. Journal of sports sciences, 36(6), 691–696. https://doi.org/10.1080/02640414.2017.1331042
14. Lasevicius, T., Ugrinowitsch, C., Schoenfeld, B. J., Roschel, H., Tavares, L. D., De Souza, E. O., Laurentino, G., & Tricoli, V. (2018). Effects of different intensities of resistance training with equated volume load on muscle strength and hypertrophy. European journal of sport science, 18(6), 772–780. https://doi.org/10.1080/17461391.2018.1450898
15. Farrow, J., Steele, J., Behm, D. G., Skivington, M., & Fisher, J. P. (2021). Lighter-Load Exercise Produces Greater Acute- and Prolonged-Fatigue in Exercised and Non-Exercised Limbs. Research quarterly for exercise and sport, 92(3), 369–379. https://doi.org/10.1080/02701367.2020.1734521
16. Fink, J., Kikuchi, N., & Nakazato, K. (2018). Effects of rest intervals and training loads on metabolic stress and muscle hypertrophy. Clinical physiology and functional imaging, 38(2), 261–268. https://doi.org/10.1111/cpf.12409
17. Lim, C., Kim, H. J., Morton, R. W., Harris, R., Phillips, S. M., Jeong, T. S., & Kim, C. K. (2019). Resistance Exercise-induced Changes in Muscle Phenotype Are Load Dependent. Medicine and science in sports and exercise, 51(12), 2578–2585. https://doi.org/10.1249/MSS.0000000000002088 
18. Robinson, Z. P., Pelland, J. C., Remmert, J. F., Refalo, M. C., Jukic, I., Steele, J., & Zourdos, M. C. (2024). Exploring the Dose-Response Relationship Between Estimated Resistance Training Proximity to Failure, Strength Gain, and Muscle Hypertrophy: A Series of Meta-Regressions. Sports medicine (Auckland, N.Z.), 54(9), 2209–2231. https://doi.org/10.1007/s40279-024-02069-2
19. Lasevicius, T., Schoenfeld, B. J., Silva-Batista, C., Barros, T. S., Aihara, A. Y., Brendon, H., Longo, A. R., Tricoli, V., Peres, B. A., & Teixeira, E. L. (2022). Muscle Failure Promotes Greater Muscle Hypertrophy in Low-Load but Not in High-Load Resistance Training. Journal of strength and conditioning research, 36(2), 346–351. https://doi.org/10.1519/JSC.0000000000003454 
20. Terada, K., Kikuchi, N., Burt, D., Voisin, S., & Nakazato, K. (2022). Low-Load Resistance Training to Volitional Failure Induces Muscle Hypertrophy Similar to Volume-Matched, Velocity Fatigue. Journal of strength and conditioning research, 36(6), 1576–1581. https://doi.org/10.1519/JSC.0000000000003690
21. Nóbrega, S. R., Ugrinowitsch, C., Pintanel, L., Barcelos, C., & Libardi, C. A. (2018). Effect of Resistance Training to Muscle Failure vs. Volitional Interruption at High- and Low-Intensities on Muscle Mass and Strength. Journal of strength and conditioning research, 32(1), 162–169. https://doi.org/10.1519/JSC.0000000000001787

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