Sports Geezer is the place to find links to news about physiology, training, and research regarding the post-40 athlete.
Everyday Athlete is written by a young, female cyclocross racer who captures the passion and joy of competition, no matter what your sport. A fine writer.
Debbie Rocker writes about fitness, nutrition, and motivation. Check out her article on why we eat like pigs throughout the holidays and why we don't have to.
I have RSS feeds from all these to my home page so I don't miss anything they write.