The first thing I notice about this is that it seems to be a bit light. The background is light, which doesn't really bother me, other than the fact that it makes it look like the lighting wasn't the best for the shot.
The one thing that does bother me about the lightness of the shot is the wheels of the bike. My brain says that they should be black, but they are kind of a muted grey. This, being an advanced editing challenge, could have easily been adjusted in photoshop, if even selectively. His shirt seems to be dark in comparrison with the rest of the photo. And that looks a bit odd, but still ok.
Focus is a bit soft, obviously due to the 'action'. Shutter speed could improve that, and possibly better lighting conditions. Something totally out of your control at the moment, but non the less, something that could have been better if different.
I wish that it were more obvious that he was jumping down stairs. With the blurred background like that, it makes it look like just different colored tiles on the ground or something. I didn't realize they were steps until reading your description. I guess that would mean that it seems like it has no depth.
I think the shot definately says action though. Maybe would seem more 'extreme' if it were more apparent that he were jumping down stairs.
Who wears blue socks with red shoes anyway?