As you fall in a controlled manner in the squat (or any exercise), elastic energy accumulates, much like a spring does when squeezed, assisting you in the beginning stages as you reverse direction. Leg workouts like as barbell squats, leg presses, and dumbbell lunges enhance the hormone testosterone as well as other growth hormones, allowing you to pack on more lean muscle mass to your complete body. Of course, in order to optimize that growth, you must also workout your upper body.