Help me prepare for shooting a half-marathon

Normally I'm photographing things that aren't moving terribly quickly--My two 5d classics are totally sufficient for this.

But tomorrow morning I'm going to trot down the street to watch the Army Run (an annual run in Ottawa) and to hopefully catch a couple of my friends who will be out there doing a half marathon.

I have a 7D but have mostly been messing with video and haven't fully explored all of the features that would lead to the best results for this kind of event.

The question: in terms of custom functions, focusing modes and other areas, what do you recommend I do ? Let's presume that I'm an all-round competent shooter with a solid background looking for advanced advice for shooting in this circumstance.

I should also add that I'll have a 70-200 on the 7D and will probably plop a 50mm on a 5d as well.

In most races, you can get quite close to the runners on the sidelines. So you're 70-200 on the 7D is probably too long. The runners will be running toward you. So use AI servo.

Most people worry about the gear that they forget what makes an image. Use servo mode and if you really want to freeze the action don't go under 1/1000
Study the course map, look at the backgrounds and sun locations. Consider on race days things will be different cars won't be parked, there will be spectators etc. Consider all these when scouting the location.
Almost 90% of my stuff is shot with 16-35 and 70-200 during a race. For advertising stuff I use primes but at the race zooms have better option.
I would suggest 70-200 on 7D with wide open to isolate the subject.
Here are some stuff:
http://www.alienginpho​tography.com/blog/

Hey guys--thanks a lot for the suggestions.

As you predicted I was able to be right alongside the road during the race; but I still shot long in part so that I could take cover under a tree--yes, it indeed started raining. I also liked that I could start at 200 and then pull back to 70 giving me multiple opportunities for different framing. I had the 5d with me with a 50mm on it but I didn't even use it because of the rain.

I used zone AF, switching between left-centre-right composition as desired. I missed focus a couple of times--but I'm positive it was user error. I stayed between 1/640 and 1/1250, nearly wide open, and was at ISO 3200 the entire time, despite it being daytime.

Here are some shots from the Army Run.

I obviously don't really know what I'm doing when shooting sports and the rain didn't exactly inspire my running out into the rain to find better compositions and backgrounds (I tucked my 7d into a plastic bag with a hole cut out of the bottom); but I'd still appreciate any feedback you can offer.

The photos are way better than I was expecting, haha! I actually really enjoy photos of people running in rain more than sun because it adds a different sense of emotion.

I might suggest shooting more in portrait rather than landscape specifically for the photos where you are trying to isolate just one runner.

Also, be aware of your cropping. Cropping of your subject as well as cropping of people in the background. Cropping of a subject, I typically find cutting them off at the thighs are more pleasing than cutting them off at or just below the knees. And for all those people in the backgrounds, be careful not to amputate their arms or heads... and watch for rogue detached arms just floating into the edge of the frame.

I also usually take a burst of 3-4 shots per subject so I can choose the one where the runner's feet are BOTH in the air. When one of the runners feet have hit the ground, it's not terribly flattering for the rest of the body (especially woman).

Eyes. If the runner's eyes are closed, I'd toss it. But that's just me.

In general, very good photos!