Post-stabilization begins when the landing phase ends. The pre-stabilization and post-stabilization phases provide an initial condition for calculations involving impulse as well as center of mass velocity and position, which are sensitive to even slight movement.

Usually, you will see this error if the athlete performing the test does not stabilize after a jump or wait long enough between multiple jumps during a countermovement jump or squat jump test. To fix this, instruct the athlete to wait slightly longer between jumps.