Cool :) Now, turn your grip so that your palms face downwards, fingers point away from you before you fold them - as if you're climbing a rock or a fence. And you'll train another muscle group once again.
Also, if you want to make it a little easier and do a higher count, find a higher bar and put your feet closer to you, just below the bar itself. Will be like relaxing back a bit and closing in on the bar over and over for probably longer.
It's so easy talking or writing instead of doing it myself ;)