Back Pull-up on Ball   - (intermediate)
(Back, trunk)

1- Start by placing your feet on the ball with your body straight and holding yourself close to the bar at chest level.
2- Your hands should be grasping the bar at a distance of just a little outside of your shoulders with your forearm at a 90 angle with the bar when you are up. 
3- Go down until your arms are straight.
4- Go back to the starting position.
5- Do it 8 to 12 times.

By Sylvain Lemaire - All rights to Physigraphe.