1. Lie faceup with your arms at your sides, knees bent, and heels on the ground.
2. Lift your knees up and across the front of your body.
3. Maintaining your balance, return to the starting position.
4. Continue alternating to complete the set.
Be sure to: Keep your knees together and your shoulders on the ground throughout the move.
You should feel it: Working the hip of your balancing leg and hip flexors of the other leg.