I am no sport photographer but have a question.

last time i went to a cheerleading competition, i tried shooting in sort of the scenario you describe. these "athletes" would run towards me and then do a series of flips, making them airborne a good part of the time. i did some shooting with the 85/1.4D, but not wide open -- generally stopped down to f/2, as in the shot below. also, the 80-200/2.8, and that one wide open. all were done with a D800. if your ratio was 50-50, then i'd say you did very well. but then, the D4 is a very capable camera. my results were a bit less consistent, but the lighting was kind of poor, and i may've been able to increase my shutter speed to improve the results. still, this kind of action appears to take the system's AF capabilities close to the max.

At least his head is in focus...