Without a doubt, squats are the best exercise to build lower-body strength and establish functional movement patterns. When done properly, they target your glutes, hamstrings and quads and incorporate core stability. And there's no exercise that will make you look as good from behind as squats will. But squats — just like any other exercise — can get repetitive, and if you don't vary the way you're doing them by adding weight, changing your leg position, adding additional movements, etc., your body will adapt to that movement pattern and you'll stop seeing results. To prevent that, here are 11 essential squat variations you can incorporate into your strength-training routine. Master proper form on the basic body-weight squat first, then move on to more challenging variations as you build your strength. Your quads and glutes might be burning by the end (not to mention the potential soreness the next day), but your posterior will thank you.