Great timing, with his feet in the air. I like the composition and the backlighting too. I think a little more space at the top would have eliminated that illusion of the skateboarder hanging on to the frame to support himself.
The subject itself is interesting but he's mostly centered in the shot and everything that surrounds him is pretty dull. I'd say get in closer and make him fill up as much of the frame as you can manage to avoid including so much of the uninteresting background. And if you've got enough resolution to play with, I'd consider cropping it closer as well.
Nice motion capture but more attention needs to be paid to background and position of elements in it. In this case I feel that the position of the post on the opposite pavement (UK for sidewalk) interrupts the outline of the skateboarder. I think composition also needs attention - this might work better in portrait and would benefit from additional space at the top to balance that at the bottom and ensure the skater's hand were not chopped off.
This is a good action shot. I realize it is difficult to control the backround in a captured shot but I find the telephone poll and the bottom of the house above distracting. I think I would have liked your picture better if the entire shadow was included.