Tendinosis. Tendinosis is the breakdown (degeneration) of the collagen fibers in your tendon. It happens slowly and is often the result of tendon overuse.
Tendinosis: Tendinosis, a chronic condition, occurs when collagen in your tendons has accumulated many torn fibers within the tendon which weakens the tendon thus deteriorates the tendon structure. Tendon overuse causes tendinosis. It most commonly happens in the elbow, heel, knee, shoulder or wrist.