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.