If you’ll excuse the pun, every athlete, whether amateur or professional, has an Achilles heel. Soft tissue injuries of the muscles, tendons and ligaments are extremely common in active people — no matter what the activity — and most of these injuries result from the overuse of tendons. Strong tendons deliver strength, power and speed — derived from their intact composition of extracellular matrix collagens, proteoglycans and elastic fibers — but they are also highly prone to injury.