A rep, or repetition, is the controlled movement of weight from a starting point to an ending point within the context of resistance training. A set consists of the number of reps executed in one sitting before putting down the weight to rest.
Dividing weight training into reps and sets allows a trainee to plan a workout that best meets his needs, as different schemes have different physiological impacts. Lifting heavy weight such that muscular failure occurs after two to three repetitions emphasizes absolute strength, whereas weight in the six to 10 repetition range encourages muscle volume. Lifting more than 10 repetitions in a set focuses on muscular endurance.