This is why using a slightly deeper countermovement often increases jump height, because the larger range of motion allows the muscles to exert force for a longer duration of time before take-off. Jump height *can* increase even though the force produced is almost always smaller. (Force is smaller when the countermovement is deeper partly because shortening through a longer range of motion leads to a faster contraction velocity, on account of the force-velocity relationship, and partly because the leverage of bodyweight on the lower body joints is larger with a deeper countermovement).

The method described above is the most common and simplest way to measure one's vertical jump, but other more scientifically accurate methods have been devised. A pressure pad can be used to measure the time it takes for an athlete to complete a jump, and then using a kinematics equation (h = g × t2/8),[4] the computer can calculate his or her vertical jump based on the time in the air.
×