2010-01-13T10:21:37Z (GMT) by
Most sports movements have an aerial phase. In sprinting the runner spends less than half of the time in contact with the ground (Hopper, 1973) while in the triple jump the aerial phases are much longer than the contact phases (Hay and Miller, 1985). Typically tennis players are off the ground when the ball is played (Elliott, 1989) and basketball players release the ball while airborne (Hay, 1985). The same is true for the release in the discus and shot events (Hay, 1985). In jumping activities it is the aerial phase that is evaluated to give a score for the performance. In the long jump and high jump events the horizontal and vertical displacements during the aerial phase are used as measures of performance while in trampolining and diving rotation and aesthetics are also included in the evaluation. In an aerial phase of a sports movement the athlete is freely falling under gravity. In freefall the balance mechanisms of the inner ear do not operate normally since they too are in freefall (Graybiel, 1970). The otolith and semi-circular canals can no longer provide information on the orientation of the head relative to the vertical direction. They do, however, give information on linear and angular accelerations (Wendt, 1951) which can be used by athletes to help control aerial movements (Yeadon and Mikulcik, 1996).