by POPSUGAR Fitness 6

Lying on your belly and doing double leg lifts really works your hamstrings, booty, and back. There are many variations you can do to keep this move from getting boring. I've already shown you how to do one type while lying on the ball and one called Superman that involves no ball. Here's a more challenging variation where you hold the ball between your feet. It not only targets your lower body, but you'll strengthen your upper back and shoulders, too.

To learn how to do this move, read more.

• Lie on your belly and hold an exercise ball between your feet. Engage your abs and extend your arms straight out in front of you.
• As you inhale, squeeze the ball and lift your knees, arms, and chest off the floor. Hold for a count of 10 and then slowly release your body back to the floor. Repeat for a total of 10 lifts.