Does Number of Sets Matter to Build Muscle?

This is probably one of the most common questions among people who want to gain muscle mass. For many years, people have been arguing about what number of sets should be done so that it affects muscle growth. In this matter, the best approach is to consider available research.

What is meant by a “set”?

During strength training, you can do both a warm-up and 20 reps to failure, depending on desire. In this article, “set” refers to the number of repetitions of a particular exercise of medium and high intensity (about 8 or more repetitions).

The number of repetitions and muscle protein synthesis

Strength training is known to stimulate protein synthesis. When the process of protein synthesis exceeds the rate of its cleavage, the muscles grow. Increased protein synthesis occurs after training and lasts for 24-48 hours. If strength training affects muscle hypertrophy, it can be assumed that the synthesis of muscle protein.

One study compared the effects on muscle protein synthesis of 3 sets and 1 set of leg extension exercises. Protein synthesis after meals was double that after 3 sets, compared to 1 set. Since muscle protein synthesis correlates with an increase in muscle volume, it can be concluded that 3 sets will positively affect muscle gain.

In another study on the effect of the number of sets on muscle protein synthesis, 6 sets of 8 repetitions made it possible to synthesize more muscle protein 2 hours after training, compared with 3 sets.

In the third study by Damas and colleagues, 12 sets with 2-minute breaks between them (6 sets of flexion and 6 leg extensions) caused a slight increase in muscle protein synthesis compared to 8 sets to failure.

The increase in muscle protein synthesis was not associated with greater muscle hypertrophy over 8 weeks, suggesting that it may be associated with minor muscle damage. Finally, one rodent study showed that muscle protein synthesis increased with the number of electrically stimulated muscle contractions.

Given the results of these studies, we can conclude that a greater number of sets affect the synthesis of muscle protein.

Number of sets and anabolic signals

During strength training, signals are sent to muscle cells to start synthesizing new proteins. It was found that a molecular signal (phosphorylated p70S6K) correlates with an increase in muscle size 5 hours after training.

Another anabolic signal is the mechanical target of rapamycin or mTOR, which regulates muscle protein synthesis. In this study, 6 sets led to a higher mTOR phosphorylation (12%) compared with 2 sets.

In general, data on anabolic signals suggests that “the more, the better.”

Number of sets and satellite cells

Muscle fibers have nuclei that are the “control centers” of these fibers and contain important genetic information. To restore or build new muscle fibers, new kernels are needed. When a muscle fiber is damaged, satellite cells give up their nuclei so that the fibers recover and grow. Thus, the process of activation of satellite cells is extremely important.

Only one study examined the effect of the number of sets on the activation of these cells. In it, 3 sets of leg presses led to greater activation of satellite cells than 1 set.

Over the past few decades, many studies have been conducted that examined changes in muscle size with a different number of exercise sets.

The results varied: in some studies, an increase in muscle mass was shown with more sets, while in other studies, there were no significant differences with more sets. Differences in the results between studies can be related to the design of the research, to the participants, the frequency of training, etc. However, the key factor that can explain the differences is the sample size.

Since there was not enough data on the subject, a meta-analysis was carried out in 2010 regarding the effect of the number of sets on muscle growth.

It was found that several sets of one exercise led to greater muscle growth than one. The number of sets was divided into 3 categories: 1 set, 2-3 sets, and 4-6 sets.

Six years later, more research appeared, and the meta-analysis was supplemented and published in the Journal of Sports Science in June 2017.

It confirmed the relationship between the number of sets and muscle growth. A larger number of sets have also been included in the meta-analysis.

The frequency of training is also important. According to a meta-analysis published in 2017:

• training 1 time per week (10+ sets ) either does not affect in any way or negatively affects the growth of muscle mass;
• training 2 times a week (10-19 sets ) is favorable for muscle growth;
• training 3 times a week (20+ sets ) is the best option.

A study by Radaelli and colleagues showed that beginners could successfully gain muscle mass with a small number of sets. Those who train for a long time should increase the number of sets. Thus, the data suggest that 8 sets per muscle group per training will be enough for experienced athletes and 2-3 sets for beginners.

How many sets would be too much?

Barbalho and colleagues studied the effect of different numbers of sets on the thickness of muscle fibers in young women and men.

Thus, we can draw the following conclusions:

• The number of sets affects the synthesis of muscle protein, and the more of them, the higher the synthesis of muscle protein.
• The more sets – the more often metabolic signals.
• More sets – more activation of satellite cells (satellite cells).
• The frequency of training is important: you should not do a very large number of sets in one training session, the best strategy is to train 3 times a week (20+ sets).
• Beginners can gain muscle mass with a small number of sets(2-3). For experienced athletes, 8 sets per muscle group per training will be enough.

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