Dude, how old are you?
I was at a block party on Memorial Day weekend and the neighbors rented a huge inflateable slip and slide thingamabob. Anyway, I am 37, and the only adult playing on the thing, and started doing flips onto it, and next thing I know, I pull a hamstring and cannot walk (one week off from wakeboarding, is all I can think of!)
So, I am assuming that you have done these flips all your life, but are getting older and the old body isn't keeping up with you nowadays.
I feel for you..:cheers: