From what I hear, Armstrong is a freak of nature with highly efficient lungs which prevent him from developing as much lactic acid as other mere mortals from the same amount of exercise.
That's Neal in the comments to this post. But it turns out that lactic acid is something entirely different:
The notion that lactic acid was bad took hold more than a century ago, says George Brooks, a professor in the department of integrative biology at the University of California, Berkeley. It stuck because it seemed to make so much sense.
"It's one of the classic mistakes in the history of science," Brooks says.
As for the idea that lactic acid causes muscle soreness, Gladden says, that never made sense.
"Lactic acid will be gone from your muscles within an hour of exercise," he says. "You get sore one to three days later. The time frame is not consistent, and the mechanisms have not been found."
And yet, this is going to take forever to filter out to the peoples. One reason is that the lactic-acid-management method of coaching works, just not for the reason they think it does.