Want a firm butt? Try glute bridges on a medicine ball.

Glute bridges on medicine ball - PICTURE - Women's Health & Fitness

Targets: Glutes, hamstrings

How to

Lie flat on your back and place both heels on top of the medicine ball.

Push your heels down through the medicine ball and raise your hips up to a bridge position.

Lower your hips back down to the starting position.

Repeat and complete as many as you can in the recommended amount of work time.

Next: 4 key exercises for a firm bum>>

Workout from Nichelle Laus; photo credit: Dave Laus.