Get the Flash Player to see this player.

This is a rather extreme exercise that needs to be performed with caution.  Here I use the Ballast Ball beneath my feet while doing pull-ups.  You want to make sure you never let go of the bar to keep this exercise safe.  Changing the amount of weight you put into the ball, or only using one leg on the ball, makes this a challenging and fun exercise.  Be careful & have fun!