In strength training, a compound set is a pair of exercises that are performed back to back with no rest in between. Unlike supersets, however, in which the exerciser alternates between sets of exercises for two different, or opposing, muscle groups, compound sets involve performing two exercises for the same muscle group back to back. A compound set for the chest, for instance, might include a barbell bench press followed by a push-up. Benefits of performing compound sets are that a given muscle group can be fatigued in less time, making the workout more efficient. Another advantage is that the muscle group can be brought to fatigue more completely by targeting as many different aspects of the muscle as possible.
When training a muscle group like the back, which is made up of many muscles ranging from the trapezius in the upper back to the latissimus dorsi along either side of the back, a strength workout for that group can be time consuming, especially when paired with a secondary muscle like the biceps. It also can be difficult to work a given muscle to exhaustion, a necessary component of optimum muscle building. Utilizing the compound set helps reduce not only the time required to complete the workout but also the total number of exercises in the workout for the muscle group being trained. For example, pairing an exercise for the lats like a lat pull-down with one that focuses on the rhomboids between the shoulder blades like the reverse fly forms a compound set that targets two muscles in quick succession. Another combination that could be performed for the back includes dumbbell shrugs for the upper trapezius followed by single-arm dumbbell rows for the rhomboids, middle and lower trapezius, and lats.
Organizing the strength workout this way also ensures that an optimum number of muscles are fatigued as completely as possible. Since the compound set targets multiple muscles in a group from several directions, more muscle fibers are recruited in all to perform the work required. Muscles contain a few kinds of fibers, some that are better suited to low-intensity, higher-endurance work and some that are better suited to high-intensity, quick-burst activity. Using the compound set increases the likelihood that the different fiber types are trained in a single workout, which encourages greater potential muscle growth over a briefer period of time.
While expert recommendations may vary on how to structure a compound set workout, one method is to perform two or three compound sets, or four to six total exercises, for a given muscle group. This may be followed by one or two compound sets for a secondary muscle group, such as the triceps following a chest workout. Not only is the secondary muscle group smaller in size, but as these muscles assist those of the larger group in the first round of compound sets they will already be partially exhausted, or pre-fatigued. Each compound set should be performed four to six times with no rest between the two exercises and for a total of eight to 12 repetitions. Experts recommend resting 30-90 seconds between each compound set before repeating.