The vertical jump is a commonly used test to assess muscular power of the legs. 123456 Power is defined as (force X distance) I time. Thus, performing the vertical jump and producing great muscular power depend on the ability to produce a high level of force very rapidly. There are two primary ways to test the vertical jump: the squat jump and the countermovement jump. During the squat jump’ the subject lowers into the squat position’ pauses for a moment’ and then jumps vertically as high as possible. During the countermovement jump’ the subject starts from a standing position’ descends rapidly into a squat position’ and then’ without stopping at the bottom of the squat’ performs a maximal vertical jump. The countermovement jump results in jump heights that are approximately 2 to 4 cm higher than the squat jump. 1 This occurs because there is a rapid transition from the descent (eccentric phase) to the ascent (concentric phase) of the movement. The squat jump’ however’ tends to result in more reliable scores’ presumably due to the variability associated with the countermovement. In addition’ muscular power of the legs is more accurately estimated using the squat jump than the countermovement jump. 5