depends, with everything, u gotta see the worst thats gonna happen, backflips, if u screw up and worst comes to worst, you land on your head....your spine curls naturally that direction so the injury is going to be LESS sever as if the same happend while trying a front flip, which you could land half way around on your head, and dig your face while your feet swing around and break ur back....i'd go backflip unless you are positive you can get at least to your back....and remember-a frontflip over a jump is more like a 1 1/2 flip and a back flip is more 3/4 flip....go back flip