Best Bodyweight Exercises for a Strong Core
Raised Knee In
Lie on back, arms along sides, palms down and just under lower back and butt. Press the small of your back against the floor and extend legs outward, with heels about 3 inches above the floor. Keeping lower back against the floor, lift left knee toward chest. Your right leg should remain hovering above the floor. Hold, then straighten left leg to the starting position and repeat with right leg.