Tone the backs of your thighs, glutes, and your core with this targeted isolation exercise.
How to do it: Start kneeling and bend both elbows down to the floor below your shoulders, hands clasped. Extend your left leg up and behind your body, pointing your toes as the leg extends [A]. Next, bend your left knee and draw your left leg in, lightly tapping the back of your right knee with your left kneecap [B]. Extend left leg back out and repeat 15 times total, then switch legs and repeat (if you want to really feel the burn, try doing two sets of this exercise before moving onto the next move).
Quick Form Tip: Press both arms down into the floor to avoid collapsing into your chest, and keep your abs drawn in tight so that your lower back doesn't sag.