TAKE-OFF TECHNIQUE IN THE HIGH JUMP

Abstract

INTRODUCTION: Alexander (1990) produced a model of jumping that predicts optimum techniques that are in good agreement with those used by high jumpers and long jumpers. We have refined Alexander’s model and used it to more closely examine the take-off technique in the high jump. In particular, we examined the sensitivity of the athlete’s performance to deviations from the optimum technique, and the dependence of the optimum technique on the athlete’s leg strength and leg length. The results from this work are to be incorporated into a biomechanical analysis program conducted for Athletics Australia. The aim is to improve the performance of Australian high jumpers through relevant and timely biomechanical analysis. Similar work investigating the take-off in the long jump is also in progress. METHODS: The mathematical model incorporates the geometry of the athlete’s legs and the properties of the leg extensor muscles. In this model, the leg angle is the angle between the ground and the line joining the foot to the hip; and the knee angle is the angle included between the thigh and the shank. The model’s anthropometric values were adjusted to be representative of elite male and elite female athletes, and many jumps were then simulated with various run-up speeds and angles of the leg and knee at touchdown. RESULTS: The simulations predict the observed differences between male and female athletes in their optimum take-off technique (Dapena et al., 1990). Because of their longer legs and greater leg strength, male athletes should use a faster run-up and have a greater leg angle at touchdown than female athletes. For an individual athlete, jumping performance is only moderately sensitive to deviations from the optimum take-off technique. As training increases the athlete’s leg strength, the optimum jump performance improves, but the run-up speed must be faster, and the leg angle at touchdown must be increased. The simulations also predict the observed changes in jump performance, leg angle, and knee angle as an athlete uses a progressively faster run-up (Greig and Yeadon, 1997). It is planned to use the model to investigate the effect on jump performance of the athlete’s crural index, and of the design of the jumper’s shoe. CONCLUSIONS: This relatively simple model accurately predicts the observed relationships between the performance parameters in elite high jumpers. REFERENCES: Alexander, R. (1990). Optimum Take-Off Techniques for High and Long Jumps. Philosophical Transactions of the Royal Society of London, Series B 329, 3-10. Dapena, J., McDonald, C., Cappaert, J. (1990). A Regression Analysis of High Jumping Technique. International Journal of Sport Biomechanics 6, 246-260. Greig, M. P., Yeadon, M. R. (1997). The Influence of the Approach on High Jump Performance. Athletics Coach 30, 10-13.