I agree with Veronica - rides of those type do tend to attract a more mature crowd, but I can also tell you in the racing community it is not necessarily the young pups that are the fastest - at least among the women. Most of our fastest women also qualify for masters racing and some are even 50+

Also if you look at longer events, more geared towards endurance than raw power I think that the differences between younger people and older folks even out quite a bit. More experience and more base mean riders who have been at it longer do just as good if not better.