Do More Sets Build Muscle?
Everyone wants to build muscle fast, right?
The average bodybuilder will spend at least an hour and a half in the gym and typically do more than 20 sets per body part for arm training. The legendary Arnold Schwarzenegger would spend all day in the gym, with workouts twice a day consisting of 20-30 sets per body part. It has been suggested that more sets build muscle. A large volume of resistance training stimulus promotes more extensive metabolic stress and mechanical tension resulting in more substrate depletion, metabolite accumulation, and muscle damage.
These factors, in turn, trigger anabolic responses during recovery that lead to muscular hypertrophy. A number of reviews and meta-analyses over the recent years have evaluated the effects of multiple sets of exercise to induce muscular hypertrophy. The use of higher set volumes is recommended for increased strength and muscle mass gains, with the belief that more sets build muscle. However, some reports suggest that when the number of sets is too high, there is a decrease in testosterone, combined with an increased cortisol secretion. The real goal of resistance exercise is to determine the minimum amount of sets to trigger increases in lean muscle mass without stimulating excess cortisol production, instead of hoping that more sets build muscle. A 2015 study found no added value in increasing the number of sets in the high set volume cohort (i.e., no difference between 21 sets and 15 sets), although this may have stemmed from the fact that the 21 sets training program induced too extensive muscle damage for optimal muscle growth. Another study showed that four to six sets per muscle group per training session were more effective than ≥9 sets.
Recent studies examining the effect of set volume per muscle group on upper body muscle hypertrophy generally found no significant difference between low (<3) and high (≥3) sets per muscle group. These findings corroborate the principle of general adaptation, which affirms that there is an optimum dose of weight training stimulus for the desired training-induced responses occur. Based on the hours and infinite sets that top-ranked bodybuilders perform every day in the gym, there is insufficient evidence to support putative notions that larger volumes (≥3 sets) are statistically superior to low set volumes for upper body muscle growth for these individuals. There is little evidence to support that more sets build muscle.
La Scala Teixeira CV, Motoyama Y, de Azevedo PHSM, Evangelista AL, Steele J, Bocalini DS. Effect of resistance training set volume on upper body muscle hypertrophy: are more sets really better than less? Clin Physiol Funct Imaging. 2017 Oct 11. doi: 10.1111/cpf.12476.
Radaelli R, Fleck SJ, Leite T, et al. Does response of 1, 3, and 5 sets of resistance exercise on strength, local muscular endurance, and hypertrophy. J Strength Cond Res (2015); 29: 1349–1358.