Posted: December 16, 2004

Science of Sport: Should It Be One Set - Or Three?

By Owen Anderson, Ph. D. - Copyright © 2002-2004

It's as straightforward as tying your shoes: When you go to the gym to improve your strength for running and to add a few strips of sinew to your upper body, you complete three sets of each of your chosen strengthening exercises, not just one or two - and not as many as four. Three is the magic number - the quantity of sets which will optimize your gains in strength over time. Whether you are bench-pressing, leg-pressing, biceps curling, hitting lat pull-downs, or performing any other kind of resistance exercise, you believe that three sets must be performed before you can consider your routine to be complete.

But do you really need all three of those sets to optimize your strength for running? It's possible that the first set provides most of the physiological stimulus for your muscles to get stronger, with the second and third sets offering little more than upgraded calorie-burning. Indeed, recent research indicates that you might be able to get by just as well with one set as with three. In research carried out in the Department of Exercise and Sports Sciences at the University of Florida, 42 adult weightlifters (average age 40) with a mean of six years of weight-training experience were divided into two groups (1). One group performed one set of a nine-exercise resistance-training circuit three times a week for 13 weeks, while a second group performed three sets of the same resistance-training circuit (also for 13 weeks, with three workouts per week). The exercises included such popular exertions as leg extensions, leg curls, chest presses, overhead presses, and biceps curls, and for each exercise eight to 12 repetitions were performed to muscular failure (that is, the resistance for each drill was set so that subjects could complete at least eight reps but not more than 12 reps; the intensity could thus be called the "eight- to 12-rep max").

After 13 weeks, both groups significantly improved muscular endurance while doing chest presses and leg extensions (muscular endurance was defined as the number of repetitions to failure using 75% of the pre-training one-repetition maximum for each exercise). Both groups also significantly improved one-repetition-maximum strength for the five key exercises, and both groups significantly upgraded lean body mass. The key finding, however, was that the one-set lifters improved just as much in all three characteristics (endurance, one-rep-max strength, and body composition) as the individuals who toiled three times as long with their trio of sets!

Citing findings such as these, supporters of the one-set theory like to tell multi-set trainers that they are wasting a lot of time during their workouts. The one-set folks argue that athletes would be better off doing just one set of any particular exercise and then moving on to a different exertion which could produce a differing type of sport-specific strength, instead of yoking themselves to unproductive repetitions of a limited number of movement patterns.

However, it should be noted that not all research puts one-set strength training in a glowing light. In a recent study completed by one of the most respected figures in strength-training research, Dietmar Schmidtbleicher of Johann Wolfgang Goethe University in Frankfurt am Main, Germany, three sets were actually superior to one (2). In Schmidtbleicher's investigation, 27 experienced female strength-trainers (aged 20 to 40) were randomly placed in either a single-set group, a three-set group, or a non-training control group. Both of the training groups took part in a whole-body strengthening program, working out twice a week for six weeks while using exercises such as bilateral leg extensions, bilateral leg curls, abdominal crunches, seated hip adductions/abductions, seated bench presses, and lateral pull-downs. The single-set group utilized one set of six to nine repetitions to failure (six- to nine-rep-max) of each exercise per workout, while the three-set group used three sets per workout with the same intensity; the rest interval between sets was two minutes.

Before and after the six-week training program, all subjects were tested for their one-repetition maximum strength on the bilateral-leg-extension and the seated-bench-press machine. As it turned out, maximal strength gains were greater in the three-set group, compared with both the one-set athletes and controls. For example, maximal strength in the bench press increased by 10% in the three-set group but did not increase significantly in the one-set lifters or in the control subjects. Although both the three- and one-set groups made significant strength improvements in leg extension, the advances tended to be larger in the three-set athletes (15% vs. 6%). One of the nice features of this study was that it focused on female strength-trainers; work in this area has almost exclusively centered on males.

In an even-more-recent investigation completed at Arizona State University, three-set training was also the clear winner. In this study, 16 experienced strength-trainers (average age 21) were equally divided into one-set or three-set groups, both of which trained three times a week for 12 weeks (3). One-repetition maximums were recorded for all 16 athletes for both the bench press and leg press before the study began, midway through the investigation, and after the 12 weeks of training were completed. The subjects focused on the bench press and leg press during their training, utilizing an undulating-periodization pattern and intensities of four-rep max and eight-rep max. After 12 weeks, three-set trainers upgraded their leg-press one-rep-max strength by 56%, from 226 to 344 kilograms, while one-set athletes inched leg-press puissance upward by just 26%, from 269 to 337 kilos; this difference between groups was statistically significant. For the bench press, three-set athletes upped one-rep-max strength by 16% over the second half of the 12-week period, while the one-set folks managed just a 3-% hoisting of strength over the same time frame; again, this disparity was statistically significant.

Which investigation(s) should one believe? Bear in mind that the one- versus three-set controversy cuts to the heart of the basic question concerning what aspect of exercise actually stimulates muscles to adapt in ways which boost their strength. One theory is that training at high intensity (i. e., with high muscle tension) is the most-important factor for improving maximum strength (4). According to this theory, the number of sets completed would be of relatively minor importance; the crucial factor would be the exposure of muscles to high tension levels, something which could easily be accomplished with one set.

However, many exercise physiologists believe that maximization of strength also hinges on the creation of a significant fatigue stimulus within muscles. Supporting this principle, research has shown that long, fatiguing isometric contractions produce greater gains in maximum strength than shorter, less-fatiguing isometric contractions, even when the time duration of muscle activity is equivalent. For example, one study found that four, highly fatiguing 30-second contractions induced superior maximum strength, compared with 40 three-second contractions of the same muscle group, even though the amount of time in contraction - 120 seconds - was exactly the same in the two cases (5).

An ingenious recent study also supported the induction-of-fatigue mechanism for creating maximal strength. To spike fatigue in the muscles undergoing strength training, scientists actually applied tourniquets to the subjects' limbs in order to produce ischemia in the working muscles (6). Four weeks of training with tourniquets (and thus reduced blood flow to the active muscles) did not compromise the gains in strength achieved by the muscles. In fact, the muscles with tourniquet-restricted blood supplies (and thus, in theory, the greatest amount of fatigue) actually made superior gains in strength, compared with muscles with normal blood flow!

The fatiguing-isometric and tourniquet studies support the notion that three-set strength training would be superior to one-set work, since fatigue levels in the relevant muscles would be higher in the former. Indeed, although research findings are inconsistent, the scientific scales seem to be tipping in the three-set direction (7). At present, continuing with your three-set pattern of strength training (or shifting from one to three sets if you have been a member of the one-set school) would seem to be a reasonable thing to do. Three sets can provide muscles both with enough intensity and enough fatigue to induce the largest-possible upswings in maximal strength. ©

References

(1) Medicine and Science in Sports and Exercise, Vol. 32(1), pp. 235-242, 2000
(2) Journal of Strength and Conditioning Research, Vol. 15(3), pp. 284-289, 2001
(3) Journal of Strength and Conditioning Research, Vol. 16(4), pp. 525-529, 2002
(4) European Journal of Applied Physiology, Vol. 52, pp. 139-155, 1984
(5) European Journal of Applied Physiology, Vol. 71, pp. 337-341, 1995
(6) European Journal of Applied Physiology, Vol. 77, pp. 189-191, 1998
(7) Strength Conditioning, Vol. 20, pp. 22-31, 1998

By Owen Anderson, Ph. D.

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