Exercise, injury and chronic inflammatory lesions.

The increasing frequency of injury over the last two decades reflects the activities of a more exercise conscious public. However, all too often injury may be due to ill-advised or inappropriate exercise and can be prevented by relatively simple modification of technique, equipment or gait abnormalities. Nevertheless, many injuries may simply reflect overtraining and the effects of repetitive strain on soft tissue and bony structures. This has led to an urgent need to understand better the mechanisms of injury, the importance of chronic inflammation and the factors involved in recovery of soft tissue strength. In the case of injuries to tendons or ligaments it is often difficult to define the contribution to symptomatology of collagen breakdown or chronic inflammation as a response to this. Furthermore, radiological changes at tendon and ligament attachments (entheses) through overuse can be indistinguishable from chronic inflammatory conditions such as spondarthritis, adding weight to the view that the body has a limited number of ways in which it can react to a variety of chronic stimuli. Marathon runners or footballers, for example, may develop symphysitis through chronic loading and radiologically there may be apparent erosive changes. Rheumatologists, dealing primarily with the chronic inflammatory arthritides, are beginning to understand better the factors involved in chronic inflammation and the effects of exercise. The Sports Physician must equally be aware of some of the pitfalls of misdiagnosis because of the masquerading of some primary inflammatory conditions as soft tissue injury or 'traumatic' joint effusion. This article will therefore review advances in current understanding of the influence of exercise on chronic inflammation and on recovery of tissue strength in sporting injuries. Improving understanding should lead to more defined rehabilitation programmes and a reduction in the all too common reinjury cycle.