Plank Leg Extension
1. In prone position, support your upper body with your hands, your arms straight below your shoulders. Your legs should be straight and hip-width apart.
2. Keeping your abs tight, exhale, and squeeze your gluteal muscles to raise your right leg, lengthening your body as your weight transfers from your arms to your left foot, stretching through your heel.
3. Return your right foot to the floor. Repeat 10 leg extensions on that side, holding a straight plank position throughout the exercise.
4. Switch legs, and repeat 10 times on the other side.