whoawhoa said:
Yes. What's more, I think this can be a perfectly legitimate, if unintentional, benefit of the folkloric "lotsa-base, weights-in-the-winter," approach.
I was thinking about this on the ride in this AM. Realistically, for most "trained" cyclists who've been at it for more than a few seasons, you can get into a "trained" state (say, ~95% of peak condition) relatively quickly; a couple months really ought to do it. The benefit of all those weights and cross-training and whatnot is simply keeping you healthy, active, and somewhat mentally fresh for the real work of training for the year. So, maybe "weights" don't help, per se, but perhaps they help avoid long-term burnout by providing a distraction that keeps the rider off the bike for at least a month or two out of the year. Anything would do: kickball, pilates, judo, etc., as long as it kept you from riding the damned bike. Weights may have the additional benefit of placebo, since so many riders swear by them.
One major, major downside of the emphasis on avoiding overtraining is the "institutionalized overtraining" phenomenon:
http://www-rohan.sdsu.edu/dept/coachsci/csa/vol13/rushall7.htm
Keep in mind that there are no surefire physiological markers for overtraining; as near as anyone can tell, the simplest explanation for it is that it is psychogenic. By worrying about overtraining, you might set unintentionally foster a fragile, delicate self-image, and end up interpreting any little twinge of fatigue or a few bad workouts as "overtraining." Ironically, your best bet to avoid overtraining might be to not worry about it.