AF Q+A: ARE LOW REPS REALLY BEST FOR INCREASING MUSCLE SIZE? Strategies to increase muscle size, strength and racing speed. by Matt Brzycki Facebook Twitter LinkedIn Pinterest According to weight-room lore, doing low reps with a high load increases muscular size, and high reps with a low load improves definition or tone. But there’s little scientific support. In a recent study, 18 male subjects (average age 23.3) were matched for baseline strength and split into two groups: One did 25–35 reps per set, and the other group did 8–12 reps per set. Both groups did 3 sets of seven different exercises for all of the major muscles and trained three times per week. After 8 weeks, both groups experienced significant size increases in the biceps, triceps and quadriceps. There were no significant differences between the groups. In other words, both low reps and high reps increased muscular size to the same degree. REFERENCE: Schoenfeld, B. J., et al. 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.