Cool idea. I do feel that the shadow being partially cropped out of the frame distracts a bit and it does appear that they are just jumping up in the air and not off the dock.
Easily fits challenge, but I think this photo needs something to bring out the wow, that I also seem to fail to photograph. So I pass on my average received score 5. ;p
They don't look like they're actually jumping off the dock. My guess is that you'll get hit for that. But I do like how you chose to show action and keep a personal connection in a photo that barely shows any actual people, just feet.
This would have worked much better if you had either completely removed the people, or completely included them. The floating feet are just a big distraction.