While it may look funny, it will help ensure your abs are sore for days. Plus, it gives your glutes, arms, and thighs a small workout too. To make it even more challenging, strap on some ankle weights.
How to: Lie face-up with your arms extended toward ceiling, directly over your shoulders, and knees bent 90 degrees over hips, calves parallel to the floor. Keeping shoulders down and feet flexed, engage your core and extend your right arm and left leg away from you. Tap heel to floor and return to center.
Immediately repeat on the opposite side. Continue alternating sides for 16 reps total (8 each side).
Modify: Keep your arms still and focus on your lower body, extending one leg down to floor at a time. Once you feel stronger/more comfortable, incorporate the upper body.
This article originally appeared on Women's Health US.