A workout set is the consecutive execution of a predetermined number of exercise repetitions. In resistance training, a repetition is defined as the completion of a single exercise or movement through a full range of motion. The number of sets used per exercise in a given workout is usually determined by individual goals and level of experience. Weight training beginners will usually experience significant results performing only one set per exercise during the first six to eight weeks of training. For more advanced lifters, additional sets may be required to promote muscle fatigue and encourage growth.
During the early weeks of training, a single workout set per exercise is normally recommended. Primarily, this is because the accelerated strength gains typically seen by beginners is the result of increased muscle fiber recruitment. In the inactive person, a percentage of muscle fibers in each muscle lie dormant. One set per exercise is normally enough to wake these dormant fibers, resulting in considerable increase in strength over a short training period. Performing more than one set per exercise can lead a newcomer to experience over-training, fatigue, or injury.
While the benefit of early muscle fiber recruitment is a great motivational factor for newcomers, its effects tend to wear off after about the first eight weeks of training. After this, adding extra sets per session is often recommended to see comparable results. Intermediate routines may include more than one workout set of a single exercise. Very advanced routines often incorporate a variety of supersets to increase intensity, or to target different angles of a muscle group.
There is some controversy among athletes, trainers, and exercise physiologists as to how much benefit multiple sets offer over a single workout set. Some experts contend that to adequately fatigue muscle fibers and stimulate growth, multiple sets or even supersets are necessary for the advanced athlete. Others maintain that a single set, performed at high intensity with excellent form, is a better strategy to increase size and strength.
For the average person, the best choice is generally the one that is most enjoyable. Some people enjoy dashing into the gym, performing a single workout set for each body part, and going on their way. Others live for working each muscle in isolation, using a variety of complex movements. Genetics, lifestyle, and personality all play a role in determining what combination works best, on an individual basis. In the end, whatever style motivates a person to continue regular exercise over the long term is usually the best option.