This exercise not only strengthens the hamstrings, but also increases core strength and stability.
- Begin by laying on your back, heels on the exercise ball, arms across your chest. Lift your hips off the ground so that your back and legs are aligned.
- Slowly bend your knees, pulling the exercise ball towards you. Be sure to keep your buttocks off the ground, and maintain your balance.
If you are having a hard time balancing at first, put your arms at your sides rather than across your chest.