If you’re shooting sports and the athlete is running, set your camera to shutter priority (Tv on Canon) and try 1/15 or 1/20 of a second. Over the years, I’ve found this to be a good shutter speed for most sports. Pan or move your camera at the same speed as the athlete running past you. You normally want your athlete to be on a horizontal plane with you. If they are running past you (as opposed to away from you), it’s often easier to get the desired outcome. A smooth and steady panning technique coupled with using the built in motor drive on your camera (frames per second) will increase the likelihood of getting a winning image(s).
If the subject(s) happens to be still or motionless (i.e. trees, rocks, buildings), choose the speed that matches your end objective. Remember, one speed doesn’t fit all when panning. Moving your camera at the desired speed will provide a corresponding amount of motion or blur. The slower the shutter speed, the more abstract the image(s). This is where experimenting becomes your best friend. Trial & error is the name of the game. Take a few images and then look at your camera back. If you didn’t obtain the desired outcome… wash/rinse/repeat… take as many pictures as need be.
Most of us will shoot our ICB images in the left/right format. This seems to be more common than panning north/south for some reason. Both can be highly effective and you may wish to shoot the same subject in both formats and decide which one you prefer at a later time.