What is the problem with the rejects? Why do you think the keeper rate is not high enough? Are you sure it is a focus issue? What about shutter speed and DOF? What lens are you using?
For action photos my bank has a1 set to release (not focus), a3 on 21 points (instead of 9), and a8 on 51 points. I have auto ISO set with a shutter speed minimum of 1/400, shooting in aperture priority mode.