Haven't yet, I get to within half an inch of it though if I rock back and forth.
Still, when I showed my relatives a back bridge they freaked out saying I was going to hurt myself. My back has never felt better after starting that...
I will sprint, after my legs get better, quads are killing me (doms)...:)
I love this stuff.
Here's a nice little torturous workout I "invented".
100 hindu squats, 300 rope jumps and 30 hindu push ups. Should be done in about 8:45, but in any event, less than ten minutes.
That will fry your quads. Or at least it does mine. And it certainly will get the ticker going.