The human and vertebrate interaction with the environment is done primarily through the movement. This is possible due the skeletal muscle: anatomical structure able to contract voluntarily. The skeletal muscles are made up of contractile proteins which slide one over another allowing the muscle shortening and the body force generation. This protein structure of actin and myosin maintains its organization through the connective tissue that surrounds it (endomysium, perimysium and epimysium), creating arrays of myofibrils, fibre bundles, fascicles until conform the whole muscle. All this connective tissue extends to the ends of the muscle to form the tendon.