In a compound exercise, you recruit more than one muscle. For example, the leg press movement occurs around the knee, hip and ankle joints. This exercise is primarily used to develop leg muscles. An appropriate example of the compound exercise is the squat. This workout uses various muscles in the lower body and the legs, such as calves, quadriceps, hamstrings, as well as the muscles of the lower back. Usually, compound exercises are prescribed to athletes just to ensure that their muscles are working as efficiently as possible.