How Many Sets of Exercise

During the late 1970s I was coaching track and teaching exercise science at Eastern Connecticut State University, and had just been asked to write a college textbook on strength training., I had previously conducted some research on training frequency, and I was interested in studying exercise sets. At that time, there were two standard training protocols for developing muscle strength. The first was called the DeLorme-Watkins method and involved three sets per exercise. The second was known as the Berger method, and also involved three sets per exercise

The major difference between these two training programs was the work requirements. The DeLorme-Watkins method included three sets of 10 repetitions each. However, the first set was performed with only 50 percent of the10-repetition maximum weightload, and the second set was performed with only 75 percent of the 10-repetition maximum weightload. The third set was performed with 100 percent of the 10-repetition maximum weightload, and was the only set that required a hard exercise effort. In other words, there was only one stimulus set, making this essentially a single-set training protocol.

The Berger method included three sets of six repetitions each. All three sets were performed with the six-repetition maximum weightload. That is, each set required a hard exercise effort, making it a classic multiple-set training protocol.

I conducted a small study comparing these two standard strength training programs. The results showed excellent strength gains for both protocols, but no significant differences between the training methods. Although I did not follow up this study at that time, I found it interesting that one hard set of exercise produced the same strength improvements as three hard sets of exercise.

During the late 1980s we conducted a much larger research project comparing the Nautilus principle of single-set strength training with two and three sets of strength exercise (Westcott, Greenberger and Milius, 1989). The 77 subjects were experienced strength trainees who agreed to participate in a 10-week program of bar dips and chin ups. All of the subjects were pre-tested for the maximum number of bar dips and chin ups they could complete with proper technique. The subjects were divided into three training groups. Group One performed one set of bar dips and chin ups, Group Two performed two sets of bar dips and chin ups, and Group Three performed three sets of bar dips and chin ups, three days per week throughout the study. The only difference between the three training groups was the number of sets performed during each exercise session.

After 10 weeks of training, the subjects were re-tested for the maximum number of bar dips and chin ups they could perform with proper technique. As presented in Figure 1, the strength improvements were similar for all three training protocols. All three exercise groups increased their bar dip and chin up performance by four to five repetitions. Because there were no significant differences between the three training programs, it appeared that single-set training was as effective as multiple-set training for producing upper body strength gains.

During the mid 1990s a similar study comparing single-set and multiple-set training was conducted at the University of Florida (Starkey et al. 1994). The researchers compared gains in leg strength for 38 subjects performing one or three sets of knee-extension and knee-flexion exercises, over a 14-week training period. As shown in Figure 2, both the single-set group and multiple-set group made similar strength gains. Specifically, the one-set trainees increased their leg strength (average knee-extension and knee-flexion) by 14.5 percent, whereas the three-set trainees increased their leg strength by 15.5 percent. Because there were no significant differences between the two training protocols, the researchers concluded that one set and three sets of strength exercise are equally effective for increasing leg strength.


It is difficult to understand how one set of resistance exercise can be as productive as three sets of resistance exercise for building muscle strength. After all, performing three sets of bar dips requires much more work than performing one set of bar dips. Likewise, running three miles requires much more work than running one mile, and the longer exercise duration is related to better cardiovascular conditioning. However, such does not appear to be the case with strength training. It seems that exercise intensity, rather than exercise duration is the essential stimulus for strength development.

While performing several sets of exercise uses more energy and provides a good muscle pump it may not produce a greater strength-building stimulus. Consider how muscle fibers are recruited during a given exercise set. Because they have the greatest endurance, the slow-twitch (Type 1) muscle fibers are recruited first. These are joined by the fast-twitch (Type 11A) muscle fibers, which have much less endurance. As the Type 11A fast-twitch muscle fibers fatigue, they are replaced by Type 11B fast-twitch muscle fibers, which have even less endurance. Typically, when the Type 11B fast-twitch muscle fibers fatigue, the muscle is no longer able to life the resistance and the exercise set is terminated.

After a one to two minute recovery period a second set of the exercise may be performed. However, the same muscle fibers used in the first set are again recruited in the same activation pattern. That is, you work the same muscle fibers in the same manner a second time, but you can’t really push any harder on your second set than on your first set. Therefore, it is simply the same stimulus a second time.

Let me explain it another way. If you perform an exercise set with 75 percent of your maximum resistance, you must stop when your strength drops below 75 percent of maximum. That is, when you fatigue 25 percent of your muscle fibers you can no longer lift 75 percent of your maximum resistance. If you perform a second set with the same resistance, you must again stop when you fatigue 25 percent of your muscle fibers. Because you fatigue the same muscle fibers in the same order each successive set, the basic training stimulus does not change.

Based on the research studies reviewed, it appears that one good set of resistance exercise is as effective as two or three sets for providing a sufficient strength stimulus and producing significant strength gains. Our research with hundreds of men and women show that single-set strength training is also effective for developing muscle tissue. In one study (Westcott 1995), 313 adults added 3.0 pounds of lean (muscle) weight after eight weeks of strength training (one set of 12 Nautilus machines, three days pert week).

Perhaps just as important as training effectiveness is training efficiency. The vast majority of non-exercising adults give the same reason for not performing fitness activities, namely, they don’t have time. This may be a valid concern if you perform three sets of 12 different exercises. At one minute per set and two minutes between sets, such a workout would require over 1 ½ hours each training session.

On the other hand, a single set of 12 different exercises would take about ½ hour each training session. This represents a reasonable exercise commitment for many time-pressured adults, which encourages them to begin a strength training program. Although it may not be the preferred method of muscle-building for competitive bodybuilders, single-set strength training is an effective and efficient means for attaining a high level of muscular fitness. Remember, it is the exercise intensity rather than the exercise duration that is most important for stimulating strength development.

Wayne L. Westcott, Ph.D., is fitness research director at the South Shore YMCA in Quincy, MA., and author of the college textbook, Strength Fitness: Physiological Principles and Training Techniques.


Starkey, D.B.,Welsch, M.A.,Pollock, M.L., Graves, J.E., Brechue, W.F., Ishida, Y. 1994, Equivalent improvements in strength following high intensity, low and high volume training. Medicine and Science in Sports and Exercise, 26:5 (Supplement).

Westcott, W.L. 1995., Strength Fitness: Physiological Principles and Training Techniques. Dubuque, Iowa: Wm. C. Brown and Benchmark.

Westcott, W. L., Greenberger, K., Milius, D. 1989. Strength training research: Sets and repetitions. Scholastic Coach, 58:98-100.

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Written by Wayne L. Westcott PhD

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