AKA Jumping quarter squat
The jumping squat is a concentric-only explosive movement that uses heavy loading and can improve the drive of the jerk and the finish of the snatch and clean pulls.
Set up jerk blocks or a power rack so that the bar rests at a height that places you in an approximately quarter-squat position when under the bar as you would be for a back squat. Position yourself under the bar in your back squat stance and bar position, and grip the bar tightly, pulling it against your traps securely to prevent it from moving during the exercise. Make sure you’re positioned under the bar and balanced, and pressurize and tighten your trunk before starting. Drive hard through the floor with your legs, trying to accelerate maximally to jump as high as you can. With heavy weights, you will only jump a couple inches from the floor. Partially absorb the weight as you come back down and guide the bar back down onto the jerk blocks or power rack pins. Reset tightly before the next rep.
If you’re not able to clear the floor at the top of the movement (i.e. actually jump), the weight is too heavy.
The jumping squat helps train rate of force development in the legs and hips and aggressiveness in the final extension of the legs and hips, which can improve the drive of the jerk and finish of the snatch and clean pull.
Use sets of 3-5 reps with anywhere from about 70-110% of the lifter’s best back squat. Weight should not exceed what can be done with an actual jump off the floor and reasonable speed.