Abstract

We have analyzed the consequences of ligament's mechanical properties (creep, tension-relaxation, hysteresis, sensitivity to strain rate and strain/load frequency) and sensory-motor functions (kinesthesia, proprioception and reflex activation/inhibition of muscles) in top athletes activity. Exercises with moderate intensity and frequency followed by sufficient rest and recovery results, over time, with increase in the strength of the ligament, as well as in its number and diameter of collagen fibers. Reduced physical activity or immobilization are accompanied by degenerative changes with decrease of collagen fiber's number and diameter, together with changes of the ligament-bone junction. In top athletes, the impact of hysteresis is manifested by gradually decreasing tension in the ligament, development of joint laxity, reduced joint stability and increased risk of injury. The development of a cumulative creep in the ligament with training sessions which exceed in intensity or frequency the ligament's recovery capacity, allow, at a certain moment, micro-damages in the collagen fibers with an acute inflammation that may become chronic, triggering, consequently, degeneration of the ligament and joint instability. Ligamento-muscular reflexes may be inhibitory or excitatory, as may be fit to preserve joint stability: inhibiting muscles that destabilize the joint or increasing antagonist co-activation to stabilize the joint.

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