Doing lunges with your back leg resting on a ball offers the instability you need to make your lower body work even more.
- Place the top of your left foot on the ball. Keep your right knee soft — do not lock your standing knee.
- Reach your arms forward at shoulder height. If balancing in this position is too challenging, open your arms out to the sides. Inhale to prepare.
- Exhale and actively pull your deep abs toward your spine. Bend your right knee, engage your right glute, and lunge. The ball will move back and your shin will move to top of the ball. Make sure your right knee doesn't move beyond your toes.
- Inhale to straighten the front leg. Complete three sets of 12 to 15 reps on each side.