What Factors Determine Vertical Jumping Height?

The ability to jump is important in several different sports, Therefore, an increased knowledge about factors limiting vertical jumping ability is of interest for both coaches and athletes. A common experience among coaches is that up to a certain degree almost any type of training program will increase the vertical jumping capacity, However, an increased performance level of the athlete will require more specific and individually adapted training methods. The problem is then to know which type of training is best suited for each individual athlete. The maximal vertical jumping height is influenced by a number of biomechanical and physiological factors. Ultimately, the jumping height is determined by the vertical velocity of the centre of gravity at take-off. This velocity depends on the mass of the subject and the linear impulse which is the result of the upward acceleration of the different body segments involved in the jumping action. The segmental accelerations are, in turn, caused by the muscles producing torques around the different joints. The temporal and spatial coordination pattern between the angular movements of the joints will exactly determine the final shape and size of the vertical net impulse and thus also the vertical jumping height (cf. Hay 1980). With few exceptions (e.g. Bosco 1985), earlier studies on vertical jumping have mainly concentrated on physiological (e.g. Asmussen & Bonde-Pedersen 1974, Bosco & Komi 1980) or biomechanical (e.g. Luhtanen & Komi 1978, Hudson 1986) aspects of jumping not related to any practical test which could be useful for the individual athlete. The aim of this study was to investigate the relationship between parameters of the force-time curve of the vertical reaction force in different vertical jumps and the maximal jumping height attained during a counter movement jump. If certain force-time parameters can predict jumping height and also be influenced by specific training methods, it should be possible to test an athlete for each parameter and optimize the training process on an individual basis