The scientific community continues to debate the ideal rep range for maximizing muscle growth. Historically, some experts and studies have suggested the optimal rep range for muscle growth is eight and 12 reps. (1) Does this guideline align with the findings of contemporary research? 

Dr. Mike Israetel engaged in a detailed conversation with researcher, educator, and author Dr. Brad Schoenfeld in a video released by Renaissance Periodization on July 17, 2024. Their discussion explored the efficacy of different rep ranges for muscle development and the implications of low repetitions for muscle growth. See what they had to say below:

[Related: Working Out With Arnold Schwarzenegger Made Tom Platz “Small and Fat”]

Rep Ranges

Dr. Schoenfeld’s perspective on the traditional rep range for muscle growth was initially advocating for six to 15 reps. However, subsequent research has debunked that theory.

“A study [of] untrained subjects doing leg extensions showed that there was no difference between 80 percent one-rep max versus 30 percent, which was [respectively] eight reps versus 28 reps,” Dr. Schoenfeld shared.

Numerous subsequent studies debunked the myth of a specific rep range for optimizing whole-muscle growth. Muscle gains can be achieved through a wide range of repetitions, from as few as five to more than 30, presuming the trainee uses a “high level of effort.” (2)(3)

Low Reps and Hypertrophy

Dr. Schoenfeld clarifies that although pursuing low repetitions with high intensity benefits muscle development, this approach can be harsh on the joints.

Doing very heavy loads with high volumes is a recipe for either overtraining or non-functional overreaching.

Some athletes may experience diminishing returns if they persist with the same number of sets in the much higher rep ranges. Raising repetitions to as many as 40 can make training intensity challenging. 

[Related: Rep Ranges for Strength, Hypertrophy, and Cutting]

Individualized Rep Ranges

Dr. Israetel illustrated two people comfortable with their different rep ranges:

Athlete A prefers sets of five to 10 reps and dislikes sets of 25 to 30 reps.

Athlete B feels sets of five to 10 reps did not offer as much of a pump as 25 to 30 reps.

“People who are more fast-twitch-muscle-fiber dominant may respond better to heavier loads,” Dr. Schoenfeld said. “Few people fall into that range.”

Israetel asked if there is any‌ evidence of individualized responses to rep ranges between different muscles. “It’s been postulated that type-one fiber (slow twitch) may respond better to higher rep training. There’s a logical basis for type two fibers (fast twitch) responding better to somewhat heavier loads,” Schoenfeld replied. 

Individualized Rep Range Diversity

Dr. Israetel questioned rep range diversity. Dr. Schoenfeld conducted studies using the reverse pyramid training below: 

12-10-8 reps, descending set 

15-10-5 reps, descending set

Dr. Schoenfeld observed increased muscle activation with the 15-10-5 descending set approach. Another study compared daily undulating periodization with a fixed rep range: one approach alternated between three to five reps one day, eight to 12 the next, and 20 to 30 on another.

Although the difference wasn’t significant, there was an indication that some muscles benefitted from daily undulating. Therefore, Dr. Schoenfeld concluded does not appear to be a downside.

Wrapping Up 

Dr. Schoenfeld and Dr. Israetel challenged the traditional belief that the optimal hypertrophy rep range is eight to 12. Contemporary research supports a broader rep range of five to 30-plus for effective muscle growth, provided that athletes train with high intensity.

While low rep ranges (one to three) can spur growth, they tend to be more demanding on the joints and may increase the risk of overtraining.

References

Schoenfeld, B. J., Grgic, J., Van Every, D. W., & Plotkin, D. L. (2021). Loading Recommendations for Muscle Strength, Hypertrophy, and Local Endurance: A Re-Examination of the Repetition Continuum. Sports (Basel, Switzerland), 9(2), 32. https://doi.org/10.3390/sports9020032

Vieira, A. F., Umpierre, D., Teodoro, J. L., Lisboa, S. C., Baroni, B. M., Izquierdo, M., & Cadore, E. L. (2021). Effects of Resistance Training Performed to Failure or Not to Failure on Muscle Strength, Hypertrophy, and Power Output: A Systematic Review With Meta-Analysis. Journal of strength and conditioning research, 35(4), 1165–1175. https://doi.org/10.1519/JSC.0000000000003936

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

Featured image: @bradschoenfeldphd on Instagram

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