The four functions of the muscular system are movement, maintenance of posture, joint stabilization, and heat generation, states Inner Body. The primary function of the muscles is to provide contraction in order to move the body as a whole or move materials through the body.
Muscle movement is either voluntary or involuntary, notes Inner Body. Skeletal muscle is the only voluntary muscle group in the body. It controls body movement and is performed consciously. It includes activities such as walking, jumping, typing and talking. Involuntary muscle movements are actions not consciously performed, such as the movement of materials through the body’s organs, the beating of the heart, or the digestion functions of the intestines.