great capture of the backflip - I really think it could have been better with more of a close up on the three boys, however - my personal taste here...8
Oh potentially so good, but so dark! I like the composition very much & your choice of shutter speed for this shot is appealing too - the frozen action adds an element of suspense vs. blurry motion to imply movement.
But I wish that you had done even a simple levels adjustment (or brightness/contrast) to bring this image up a little...