Biomechanical Properties of Tendons and Ligaments

Toe region for tendons and ligaments

Straightening of collagen fibres, tissues stretch easily with little force, as stretching continues - greater force required as tissues stiffen, lengthening of collagen fibres occurs due to slippage between fibrils, fibres and fascicles, if maintained in this zone fibres will return to original length when load is removed

Yield point for tendons and ligaments

Failure of some fibre bundles occurs but not all at once - e.g. ligament sprain or tendon strain, integrity maintained until complete failure - rupture of ligament or tendon

Ligament and tendon injury

When load is exceed yield point or elastic limit

Grade one ligament injury

Stretched fibres but normal ROM on stressing ligament

Grade two ligament injury

Considerable proportion of fibres torn, stressing of ligament reveals increased laxity but definite end point - ligament still at least partially in tact

Grade three ligament injury

Complete tear of ligament with excessive joint laxity and no end point - need to be wary of using pain as a guide

Tendons and cross-sectional area

Larger cross-sectional area = higher the magnitude of muscle contraction or force produced = greater tensile loads, tensile strength through a tendon is twice that of its muscle

Tendon injuries

Classified as partial, failure or complete failure - determined by how weak tendon is during contraction

Partial tear might have some strength in movement, complete tear unable to perform movement