This all depends on how many runners are competing. It's all well and good to plan to get shots of runners "when both feet are off the ground whilst they are in the upward part of their stride?", or to get "shots with one foot up and behind, other on the ground from a slightly side on perspective", but when you're trying to capture 5-10 runners in a group at the same time, one group after another for an hour or longer, you're normally VERY happy to get 1-2 full body shots and 1-2 close-ups of each runner. At bigger events, things can get extremely hectic, and you had better have fast CF cards and not be shooting large files......
How many entrants are there? My experience is panning doesn't work real well for running - it's better for biking events. Too many moving parts on a runner. I'd also suggest getting low and shooting upwards. Get a dark background if you can, like a group of trees. Bright skies can be difficult unless you're using fill flash, and if you're using flash, again, if there are a lot of runners, bring lots of batteries and be careful not to burn it out by shooting too many too often.
Typical running events are frequently more about quantity than quality.
In less hectic conditions, I think it's best to get shots coming at you, from a slight angle (<45 degrees to straight), and catching the stride with both feet off the ground is a good shot, but I prefer close-ups, taken waist up, of the runners, showing facial expressions with good exertion. Like I said, getting a good full body shot and a good close-up is ideal.