How to do it: Stand with feet just outside the shoulders and hands behind your head. Squat, keeping your knees behind your toes. After holding this position for two seconds, jump vertically. Pull the toes to your shins in midair to prepare for landing. Land in the starting squat position, hold 3 seconds, and repeat.
Prescription: 2 sets of 10 reps with 30 seconds rest between sets.