I suppose you could have had a trampoline, but that would be very dangerous for the kid to use it with a pointy object in his hand and floppy shoes. I think he probably jumped off of something out of the frame -- still dangerous though. However, I'm going to guess REAL.
The shadows on the upper child look a bit harsh compared to the shadows on the rest of the image. Plus the direction of that light indicates a flash and the flash would have to be really high (above him) to cast that light, leading me to believe his picture was captured while he was lower in the camera frame and he was later digitally moved. The lower boy's left arm also looks pasted against that background.
I also believe if that ninja turtle really existed he would have stopped those two boys from fighting. Really..what is that turtle thing?? :-D