Move 5: Clamshell and leg développé (unfold leg)
1. Lie down on one side, with your shoulder above the elbow, and knees bent in front of you parallel to your hips.
2. Make sure to remain on the side of your hips throughout the whole exercise and point your feet.
3. Open your knee to the side, then extend the leg up, stretching it entirely then bend the knee again and close the knees together. Repeat 30 times each side.
From: Harper’s BAZAAR UK