RELATIONSHIP OF LUMBAR CURVATURE AND LANDING SURFACE TO GROUND REACTION FORCES DURING GYMNASTIC LANDING

Abstract

It is postulated that low back pain is one of the most common complaints of athletes. Stanitski (1982). Micheli (1979). and Smith (1977) noted that athletes with low back pain classically exhibit functional lumbar hyper-lordosis due to tight lumbo-dorsal-fascia in conjunction with weak abdominals. Excess arching of the low back is a typical posture taken by many gymnasts. Trauma to the body has been identified as being related to impact forces (Voloshin & Wosk, 1982). Since gymnastic vaulting requires the absorption of landing forces. the magnitude of these landing forces compared to other activities must be studied. The vertical ground reaction forces during walking are approximately 120 percent of body weight (Marino & Leavitt. 1985). During running these may be 200 percent body weight (Cavanagh & LaFortune, 1980) and in volleyball 400 percent body weight (Adrian & Laughlin, 1983). Presently, there are no guidelines for the coach to identify the potential risk of injury to the gymnasts during practice of skills requiring repeated landings. In the absence of such guidelines, there remain many unanswered questions. For instance. how many landings should be performed? What type of landing surfaces should be used? What should the position of the trunk be at landing? When can one determine that there is a risk for injury? In order to develop guidelines. some of these questions must be answered. Therefore, the purpose of this research was two-fold: 1. to determine the relationship of lumbar curvature and landing surfaces to ground reaction forces during gymnastics landing, and; 2. to provide the coach with guidelines based on what can be observed using video records and what the gymnast is actually doing.