Ligament

A ligament is a short band of dense connective tissue joining bone to bone. It stabilises a joint, guiding it through the range it is built for and resisting movement outside that range. Tendons, by contrast, join muscle to bone.

They are built mostly of collagen laid down along the lines of stress, which makes them extremely strong in the direction they are loaded and vulnerable to forces from unexpected angles. That is why ankles and knees fail in twists rather than in straight lines.

They have a poor blood supply, and that single fact explains most of what is frustrating about ligament injury. Healing is slow, it is measured in months rather than weeks, and some ligaments, notably the anterior cruciate, often do not heal usefully at all without surgical reconstruction.

They also carry sensory receptors, so a ligament injury damages the joint's position sense as well as its mechanical restraint. Rehabilitation that restores strength without restoring balance leaves that deficit in place, which is a substantial part of why previous injury is the strongest predictor of the next one.

They adapt to load, slowly. Connective tissue does strengthen in response to progressive training, but it remodels more slowly than muscle does, which is the mechanical reason behind a common pattern: someone whose strength outruns their connective tissue and picks up a joint problem in month four.

That mismatch is the argument for gradual progression rather than heroic jumps, and for including balance and single leg work rather than only bilateral strength.

In practice: progress load steadily, rehabilitate balance as well as strength after any sprain, and treat a joint that gives way or swells as a reason to be assessed rather than to train through.