Many elite gymnasts perform the straight arm backward longswing on rings, as shown in the graphics sequence below. Measured peak combined cable tension during a backward longswing is typically in excess of 9 bodyweights and forces of this magnitude have been associated with an increased risk of injury to gymnasts' shoulders. This study investigated the contribution of longswing technique and the elasticity of the gymnast and rings apparatus to minimising loading at the shoulders. A three-dimensional five segment computer simulation model of a gymnast swinging on rings was developed. The simulation model was evaluated by comparing the backward longswing from a data collection (upper sequence) with a simulation of the same performance (lower sequence). The graphics sequence below indicates the accuracy of the model. During the simulated longswing the peak combined force at the shoulders was 8.5 bodyweights. Modifications to the evaluated simulation of the longswing were used to determine the effect of the gymnast's technique, his elasticity and that of the rings apparatus on peak shoulder force. Removing the arching-to-piking action of the gymnast's technique increased the peak shoulder force by 2.56 bodyweights. Removing only the lateral arm movements, which form part of the gymnast's technique, also resulted in an increased peak shoulder force (0.73 bodyweights). Removing only the elasticity of the apparatus or gymnast from the evaluated simulation resulted in smaller increases in peak shoulder force (0.62 bodyweights and 0.53 bodyweights). Although the elasticity of the gymnast and apparatus contribute to minimising peak shoulder force, this study shows that the contribution of a gymnast's technique is considerably greater.
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