Lie on your back with your knees bent and feet flat on the floor. Place a glider or paper plate under one heel. Shoulder blades should feel flat against the ground. Press your lower back against the ground and hold it there as you inhale and slide your heel out away from your body. Slide out only as far as you can keeping your lower back flat. The leg will not be completely straight. Exhale and dig your heel into the plate as you pull it back towards your body activating your hamstrings. You can alternate legs or complete all reps on one leg before switching.