Even so, the back squat does differ in important ways from the vertical jump. Primarily, it involves a much greater trunk extension turning force, because of the barbell weight on the upper back, and this likely contributes to the more hip-dominant nature of the squat over the vertical jump. Secondly, it is often performed to a deeper depth, which can alter the relative contribution of each of the hip extensors to the movement, because of their different leverages at each joint angle. And thirdly, it only involves accelerating up to midway through the movement, while the vertical jump involves accelerating right up until take-off. This also affects the relative contribution of the hip extensors, as force production will be required in the jump even when the hip is nearly fully extended, while this is unnecessary in the squat.
The simplest method to measure an athlete's vertical jump is to get the athlete to reach up against a flat wall, with a flat surface under his/her feet (such as a gym floor or concrete) and record the highest point he/she can reach flat-footed (the height of this point from the ground is referred to as "standing reach"); fingertips powdered with chalk can facilitate the determination of points touched on the wall. The athlete then makes an effort to jump up with the goal of touching the highest point on the wall that he or she can reach; the athlete can perform these jumps as many times as needed. The height of the highest point the athlete touches is recorded. The difference between this height and the standing reach is the athlete's vertical jump.