CP, no not resting heart rates, but fitness and fitness patterns mostly.
I attended every Saturday Metro meet in Brissy for over 12 months a few years back trying to get it into profit but to no avail, sad but true.
A few things I did notice by being on course were a bit of a help, but by and large not enough to profit from on a consistent basis.

The most helpful thing I did notice was if a certain few jocks were sporting a "gear change " of their own it was usually a goer. They didn't always win, but at least you could see they were trying.