Interesting choice of crop and border. Being that close on top (I'm assuming to cut out the people in the background) may be better balanced by coming in from the bottom as well - possibly at the point where the lane divider comes into focus. Great timing for the capture.
I think if you waited till he got a bit close towards centre frame this would have been a better composition. The timing with the arms and head out of the water is spot on.
I love the fact that you left so much room in front of the swimmer, makes for a great composition. It makes the viewer feel like part of the photo. Great capture. 9