Squats are not only effective for building an insanely strong lower body, but also because they deliver a number of ancillary physical benefits, including increased hormone release and improved flexibility. HOW IT WORKS: Tone the lower body by using your glutes, quads, and hamstrings to push down to a squat. Work your shoulders, back, and chest as you push yourself up through every rep. Skip the weights, this squat trainer will reduce the amount of stress on the knees and joints that occurs when you squat incorrectly. Adding this to your workout will help you develop a proper form to get the perfect squat.