9. Stability Ball Hamstring Curl: 12 reps
- Lay on the ground in front of a stability ball, keeping your hips close to the ball and your heels on top of it.
- Drive your heels through the ball and raise your hips up until they're fully extended.
- With hips extended, allow legs to extend, maintaining full hip extension.
- Curl your feet and legs back in toward your hips, keeping hips up in full extension the whole time.