This is a beginning exercise for developing power in the legs and hips.
Assume a relaxed, upright stance with feet about shoulder-width apart. For proper posture interlock the fingers and place the palms against the back of the head.
Begin by half-squatting; immediately explode upward as high as possible, extending the hips, knees, and ankles to maximum length as quickly as you can. Freeze the landing, check for quality, then begin another repetition. Work for maximum height with each jump.