Anatomy and biomechanical aspects of the gastrocsoleus complex.

The complexity of its anatomy coupled with the biomechanics of the Achilles tendon may explain the frequency of injury to this structure. Its unique characteristic of the muscle crossing three joints (knee, ankle, and subtalar joints) makes it more susceptible to injury than muscles that span a single joint. A better understanding of the contributing pathologic conditions associated with functional shortening of the gastroc-soleus complex and its effects on the normal biomechanics of the foot and ankle may improve the treatment of the many and varied pathologies that occur within the tendon itself and the associated abnormalities that occur with a tight Achilles tendon.