The Jump Squat is not only a great plyometric exercise that builds explosive power, but if done for a high number of reps is a great endurance builder as well. At the end of a workout try a set of 50 and feel the lung-searing pain down to the core of your legs. This is a powerful exercise that should be eased into. Do not go right into high rep jump squats until you have tested them and your hips, knees, and ankles can handle the stress.