My brother is sore now because he tried the same from flip. (see "my tongue is broke")
but he landed on his back as compared to my landing on my but/feet.  So we go a good laugh out of it and I think he is feeling it in his back. I hope he feels better. he's supposed to go free-running tonight. I hope mom lets me go with him. we would be going to the park so it aught to be fun.
I found the difference between free running and parkour interesting.