There is an ancient expression used in endurance sports: "It's better to be 10 percent undertrained than 5 percent overtrained." I've never been too sure what to make of this expression. I mean, isn't it best to be 100 percent perfecly trained? But of late my attitude toward this unattributed piece of wisdom has changed, largely due to the frequency with which I see athletespaticularly American distance runnersperform surprisingly well in early-season tune-up races and other races preceded by relatively moderate training, and perform poorly in peak races preceded by very high training loads.

It happened again at the U.S. National Cross-Country Championships in San Diego, which I had the pleasure of watching live. Dathan Ritzenhein blew away the field, winning by 26 seconds, despite the fact that an IT band injury had forced him to train exclusively on an antigravity treadmill until just 10 days before the event. Ritz's coach, Brad Hudson, told me after the race that he had been unsure whether Ritz should even compete, fearing that the young runner might have his confidence crushed by losing badly. He needn't have worried. Apparently his greater "freshness" more than made up for his limited fitness.

I'm starting to believe that there's no such thing as being 100 percent perfectly trained for a race--or at least that there's no way to know whether you're 100 percent perfectly trained. What the maxim that I cited at the beginning of this post now means to me is simply that one should always train somewhat conservatively in order to minimize the risk of overtraining. It's not that one should try to show up to races undertrained. It's that training is a blind process, in the sense that you cannot discern a clear line marking the threshold between undertrained and overtrained ahead of you. If you try to feel your way right up to this limit in training, you put yourself at great risk of crossing it, and I do believe that every step beyond the limit is equivalent to two steps behind it.

I think I overtrained myself slightly for my last marathon in December. This year I'm going to take a lesson from Dathan Ritzenhein and others and train with a bit more restraint. I still plan to do some workouts that are just as hard as the toughest workouts I did in my recent marathon ramp-up; I just won't do as many of them, and I will train more lightly betwen them as well. It's worth a try.