Once upon a time, I taught gymnastics. For many years, in fact -- 10 years. Which, I think, is a long time to do anything when it isn't your profession. But anyway...
I taught non-competitive gymnastics, for little ones in parent child classes all the way up to grade school girls. While I am not flexible by any stretch of the imagination (we can all remember the bag game, right?), I am fairly strong. Which means that, while not incredibly graceful, I am not too bad at tumbling.
But even I wouldn't dare to try and do things over concrete. At least not if I wanted to survive without a head injury...
Not to mention