3. Hamstring Curl
This is a great way to engage your core and lower body.
How to do it: Lie on your back on the floor with your arms extended out to the sides and calves and heels resting on the ball. Making sure to use your glutes and abs, lift your hips off the floor. While exhaling, slowly bend your knees, rolling the ball towards you using your feet. Pause for a few seconds, inhale, and straighten your legs out again. For maximum benefit, keep your hips in the air for the whole set – but you can also lower them in between if this feels too challenging at first.