Great shot; nice form on the jumper (but what do I know, I was a track mom but never participated myself). He looks to be having a great time. DOF and stop-action keeps this from looking snapshotty despite the other kids in the background.
I like this one. Great action happening. His face is well lit and you can see the concentration. Slightly untidy background but it is a bit blurred out and the line up of kids waiting is good. Exposure and saturation has brought your colours out nicely. All round this is a great shot.