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-driven robot Tendon-driven robot Tendon-driven robots (TDR) are robots whose limbs mimic biological musculoskeletal systems. They use plastic straps to mimic muscles and tendons. Such robots are claimed to move in a "more natural" way than traditional robots that use rigid metal or plastic limbs controlled by geared actuators. TDRs can also help understand how biomechanics relates to embodied intelligence and cognition. Challenges include effectively modeling the human body’s complex motions and ensuring accurate positioning, given that the tendons are prone to stretch, which costs them strength and smooth operation. TDRs are the subject of considerable research and commercial systems followed. Myorobotics