1. Lie on the floor with your head between your partner's feet and grasp their ankles or claves.
2. Bend your legs slightly and raise them with a controlled pace towards your partner whilst pressing your upper back into the floor and squeezing your abs.
3. You should bring your feet all the way to your partner's hands. He shouldn't have to lean forward to catch your feet.
4. At the top of the movement your partner needs to give a SHORT SHARP PUSH/THROW. Ensure your heels do not touch the ground, keep your core tight and at the same time avoid the urge to arch your back but keep it pressed against the floor.
If done properly this is a tough ab exercise and you should prepare with a good warm up. If you feel any lower back pain consider doing a less demanding ab exercise.
