Good timing here. You managed to find the exact moment to capture two separate motions in midway. The silhouetting works well. The car in the door frame is a bit distacting. You might have chosen a longer shutter speed to overexpose that part, and at the same time emphasize the idea of notion.
Not really digging the silhouette+movement blur, just doesn´t seem to add up to a good photograph in my books, but had you had either, that is just a silhouette or just motion blur and shown a little texture in the kids I think I might have liked this. Like the composition though.
Obviously this image has some major blur, BUT, it works in the sense of motion and dynamic energy it provides. Kids never stand still, at least not in my pics. 7