Knowing the number of sets that work for your body is vital for building muscle mass. Many experts recommend you do around twelve to sixteen sets for your large muscle groups, such as your back, chest, and legs, and about nine to twelve sets for your smaller muscle groups, such as your calves, shoulders, and arms. Although this might work for some people, this can cause others to overtrain or undertrain. This is why you must understand the way your body responds to workouts.