Hang from the bar with an underhand grip (palms facing you) at shoulder-width. Lift your legs until they are parallel to the floor, forming an 'L' shape with your body. Ensure your knees are locked and toes pointed. Keeping your legs perfectly horizontal throughout the entire range of motion, pull yourself up until your chin clears the bar. Lower yourself back down with control to a full dead hang while maintaining the L-sit position. Avoid swinging or dropping your legs as you fatigue.