Many fitness professionals incorporate strength training routines into clients’ programs in part to incite postworkout elevated energy expenditure. But how many repetitions and sets are enough to generate extended periods of afterburn? Probably many fewer than you think.

A small study of eight young overweight males pitted the traditional 3-set strength training protocol against a 1-set program. Participants completed 1 set of 10 exercises, at 10-repetition maximum (RM), targeting all major muscle groups. During a separate intervention, they completed 3 sets of the same exercises, also at 10-RM. Exercises included leg press, leg curl, calf raise, bench press, lat pull-down, shoulder press, biceps curl, triceps extension, abdominal crunch and back extension. Movements were divided into three circuits, with 4 minutes’ rest between them. Energy expenditure was then tested 24, 48 and 72 hours after the exercise session.

The researchers discovered that the 3-set protocol resulted in significantly more energy expenditure during the workout than the 1-set protocol. “However, within protocols, both the one-set and three-set protocols were significantly elevated for resting energy expenditure expressed in absolute amounts at 24 hours post, 48 hours post, and 72 hours post, compared with baseline,” said the authors. “The results of this investigation support the current American College of Sports Medicine recommendation for resistance training, which is one set of eight to 10 exercises focusing on the major muscle groups. Although this recommendation is most often cited for overall muscular fitness, the fact that a single set can elevate resting energy expenditure for 72 hours may be an important modality for weight management.”

The study appeared in the European Journal of Applied Physiology (2011; 111 [3], 477–84).