Reading the force-time curve of a vertical jump
A countermovement vertical jump produces a characteristic force-time trace measured on a force plate. As the athlete dips down, force briefly drops below body weight (the unweighting phase), then rises through the braking phase as the downward motion is arrested, peaks during the propulsion phase as the legs extend, and falls to zero at takeoff when the feet leave the ground.
Power is force multiplied by velocity, so peak power occurs not at the highest force or the highest velocity alone but where their product is greatest, typically partway through the upward push. This is why a jump is analyzed as a curve over time rather than a single number.
What the shape reveals
The depth and speed of the countermovement, how sharply force rises during braking, and the height of the propulsive peak all describe how an athlete generates explosive force. Coaches use these features to distinguish, for example, an athlete who is strong but slow to develop force from one who is reactive but lacks peak strength.
The trace is specific to the individual and the test conditions, so it is a diagnostic snapshot rather than a fixed template. This is general educational information, not training prescription.