I'd love to see comparitive srudies from different types of activity populations i.e. runners, matial arts, swimmers, Interval Trainers (pretty sure it would be extremely difficult to find very many elderly interval trainers but i could be wrong) Dancers, and weight lifters.
I wonder how many of the runners in these studies also did these activities as well? I guess what I am saying is is this a comparison between active and inactive elderly or active runners and active non runner elderly. It would make a big difference in evealuating whether the act of running itself not just a higher activity level had anything to do with the resistance to age related deterioration.