Tendon the Achilles tendon stretches as the ankle joint dorsiflexes. During the last portion of the stride, as the foot plantar-flexes (pointing the toes down), the stored elastic energy is released. Furthermore, because the tendon stretches, the muscle is able to function with less or even no change in length, allowing the muscle to generate greater force. The mechanical properties of the tendon are dependent on the collagen fiber diameter and orientation. The collagen fibrils are parallel to each other and closely packed, but show a wave-like appearance due to planar undulations, or crimps, on a scale of several micrometers. In
Tendon transfer used to restore a single function. Transfer of one tendon to restore multiple functions will compromise strength and movement. These are examples of commonly performed tendon transfers. Many of the lower extremity tendon transfers were performed during the nineteenth century to improve ambulation in polio patients due to post-poliomyelitis paralysis. In the beginning o twentieth century, tendon transfers were used to correct congenital talipes equina. Tendon transfers were extensively performed during World Wars I and II to patients with upper extremity injuries. Tendon transfer A tendon transfer is a surgical process in which the insertion of a tendon is moved,