The theory that explains the basic mechanism by which a muscle fiber generates force was proposed in 1954. That theory is known as the sliding filament theory and continues to be, with some modifications, the accepted explanation for the generation of force [34, 35]. The force generated by individual actin–myosin cross-bridges is transmitted longitudinally and laterally within the fiber. Of particular importance is the transmission of force to the Z-disk of the sarcomeres in series. Movement is finally produced when the force reaches the myotendinous junction, tendons, and joints.