Exercise science for the sake of human performance doesn't really do justice to the whole profession. I spent my grad school time doing research on subjects with knee osteoarthritis, specifically the biomechanics prior to and following treatment X.
I believe that ex sci is very necessary as our country as a whole is getting fatter and sicker, and there are some very good discoveries that come out that can be applied to specific populations. Research isn't going to cure things quickly, and it's also for the furthering of knowledge. But if researchers can find small things that people can do to be healthier or prevent disease, more power to them.
I think there should be a general separation between exercise/sport science dedicated to improved performance, and exercise science for the sake of health. The NIH is much more likely to spend money on the latter, as my advisor found out (he is looked at injury rates in runners, and didn't get the grant he'd hoped for).
If you put too much science into training and racing, I think you take away from the purity of the sport.
Just go run and do your best, have fun and enjoy yourself.