The Method for Testing the Dynamic of Take-off

Abstract

Among various sport branches there are such in which the take-off efficiency, and consequently, performing of the exercise depends upon technique and muscles ability to release the maximal energy in a short time. Long and high jumps, acrobatic jumps, ski jumps, volley-ball and basket-ball jumps should be included among the above described branches. In these sports take-offs with one or both legs are employed. Certain elements which may be treated as belonging to technique have some influence upon the efficiency of the energy released during a take-off. In the case of the features in question they are: a degree and velocity of flexion of legs' joints before their extension. On the basis of their research, Murray et al. (1970) and Scudder (1980) stated that the optimum angle for achieving the maximal knee extension strength is the angle of 120° (in isokinetic conditions). Lindahl et al. (1969) obtained similar results in isometric conditions. Osterning et al. (1982) proved that the maximal strength can be reached at the angle form 100° to 110°. Secher et al. (1976) were examining the maximal strength of the leg extensors during a take-off with one leg and with both legs. They noted obvious differences between the strength measures in both tests, which must be connected with the take-off efficiency. The above mentioned question was dealt with by Van Soest et al. (1985). While examining take-off with one and both legs of well-trained volley-ball players they obtained jumps' results: 0.31 m and 0.54 m respectively. In this paper we intend to test the take-off with one leg and the take-off with both legs employing a pendulum which makes it possible to eliminate gravity force which normally influences a take-off. Take-off tested in this way analysed on the background of the static strength of legs.