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
Achilles tendon rupture to rupture. The use of quinolone antibiotics can cause several forms of tendinitis and tendon rupture, including rupture of the Achilles tendon. The risk is higher in people who are older than 60, who are also taking corticosteroids, or have kidney disease; it also increases with dose and taking them for longer periods of time. As of 2016 the mechanism through which quinolones cause this, was unclear. The Achilles tendon is the strongest and thickest tendon in the body, connecting the gastrocnemius, soleus and plantaris to the calcaneus. It is approximately 15 centimeters (5.9 inches) long and begins near the