Quick primer: When photographers talk about F-stops, they're referring to aperture settings. Markewitz describes aperture as a diaphragm that opens and closes to let light in or keep it out. F22 is almost all the way closed-very little light gets in. F2.8 is the opposite. The formula for great action photos is a fast shutter speed and a lower-number aperture (e.g., 2.8). Fast-moving film, lots of light.
Play around with varying combinations. "For an artsy shot, use a slower shutter speed and a higher aperture to create a blurry effect," Markewitz says.