Pathological changes in the triceps surae muscle after rupture of the Achilles tendon.

Biopsy of the triceps surae muscle was carried out in 11 patients who had sustained a spontaneous rupture of the Achilles tendon during sports. All the specimens showed important histological and ultrastructural changes, the most striking being the presence of large quantities of lipid droplets within the muscle fibres. A factor common to every patient was a period of inactivity before resuming sports. Preliminary training may be valuable in producing positive adaptive changes in the muscles, and the consequent improvement in function may reduce the risk of rupture of the Achilles tendon.