For what it's worth, I use a 580 EX with an external battery pack for football. Over the last 4 years I have played with a lot of different settings. The best I have come up with is: camera in M, 1/640-1/800, ISO 6400, flash in ETTL with high speed sync enabled, FEC set to -1/3. I know the flash loses a lot of power with HSS but it is enough to give the high ISO shots a pop of color. The shutter speed is fast enough to stop most action. I use a 7D and put it in AI servo, continuous (low). With fresh batteries I have gotten three frames of flash. If there is enough light on the field I will go to -2/3 FEC.
JUst as Tim_S said. YOu will want a external battery pack. Unforatannly the 430 does not have the option to plug in a external battery pack so will want to pick up a 580 or one of the new 600 series.
Then you start looking at the battery packs. I recommend Quantum power packs