THEORETICAL AND EXPERIMENTAL STUDY ON DURABILITY OF THE CALCANEAL TENDON AND THE PATHOMECHANISM OF ITS ATRAUMATIC, SUBCUTANEOUS BREAK

摘要

The pathology of the calcaneal tendon (Achilles) presents a serious medical and social problem. This tendon is the strongest plantar flexor of the foot that plays a fundamental role in the accomplishment of human gait. Although this role has long been recognized, neither in medical nor in biomechanical literature can one find a clear description of subcutaneous break of the Achilles tendon. Its pathomechanism and the causes have not been fully accounted for. Many authors concentrate mainly on medical and biological aspects of the damage of the Achilles tendon.They often claim that the vasculature of the tendon itself plays a significant role in the pathogenesis, because the blood supply to the tendon changes with human age, decreasing substantially after the age of 30, leading both to regressive changes in the tendon as well as to a reduction of the tendon's mechanical strength. The refore a comprehensive description and explanation of this phenomenon needs an interdisciplinary approach, taking into account not only the medical and biological aspects, but also the mechanics sensu largo. The aim of the paper is to put forward a complete description of the pathomechanism of the Achilles tendon spontaneous break, within the framework of its mechanics. The conclusions are based upon a kinematical analysis of the knee joint, a trajectory determination of the point of origin of the gastrocnemius from the initial position of 90 degrees bent up to the full knee extension, and an experimental examination of uniaxial stretching of the Achilles tendon.