I really like the concept of this shot. I know how hard the lighting is in a gym and you did a good job. Would have liked to seen the top of the heads of the people in the background and think they would have looked better if blurred from your DOF and not motion (faster shutter speed would have helped that).
i get where you were going, but that's not going to get you much at dpc. fwiw, i think a horizontal composition without as much dead space might have worked better.