Accurately & quickly Measure Vertical Jump, Sprint Speed and Reaction Time. The JUST JUMP OR RUN" is a computer & pad, which measures vertical jump, foot quickness, reaction time, and sprints. There are three main operating modes. The first mode is the Just Jump" which is used for vertical jump and foot quickness, as well as a timer for shuttle runs and more. The second mode is the Sprint Timer" which is for measuring the athletes speed with excellent accuracy. The third mode is the 4 Jump" which is used to measure reactive jumping power of the athlete.