Hang from a bar, gymnastics rings or set of suspension straps.
Hang from a bar, gymnastics rings or set of suspension straps. Ensure that your legs are straight, in front of your body, and that your feet are together ( A). Engage your abs and pull down on the bar, raising both of your knees towards your chest ( B). Pause for a beat, before lowering your legs to the start position under control. Swinging is cheating.