I read a great article in the New York Times (Tue Feb 12 “Science Times”) today explaining why muscles get tired. Cyclists and other athletes have always focused on lactic acid as the culprit of tired muscles, but now researchers at Columbia University are studying muscle fibers differently. In their research, they have discovered that calcium ions actually leak into the muscle cell, causing the muscle to contract. What I loved about this article is that they used cyclists as guinea pigs: They had athletes cycle for 3 hours at high speeds and other cyclists just hand out and not exercise. All cyclists (those who rode and those who watched the Tour again to kill time) sacrificed snips of thigh muscle to determine if the calcium channels leaked in the muscles of cyclists who worked out. They did. Within a few days, the body repairs the damage and muscle returns to normal.
The scary thing is now they are developing a drug to combat calcium from leaking from muscles. This is great news for heart patients but this brings yet another angle to doping in all sports, cycling included. The article ends with this quote from Dr. Stephen Liggett, a heart failure researcher at the University of Maryland; “Maybe this is a protective mechanism. Maybe fatigue is saying you are going into a danger zone. So it is cutting you off. If you could will yourself to run as fast and as long as you could, some people would run until they keeled over and died.”
And then maybe we’re back to Darwinism being the the umbrella policy for evolution 
–Karen
2 Comments
February 13, 2008 at 22:50
[...] 13 February 2008 by Rodney Dunning A fair amount of attention has been paid by the cycling blogs to yesterday’s NY Times article on muscle fatigue. Apparently, calcium, and not lactic acid, is the culprit. Follow this link for a descent summary. [...]
February 16, 2008 at 19:04
Hey Karen,
Great information. I started upping my calcium intake last year, in addition to adding in magnesium supplements, to ward off horrendous cramps that I would experience after cycling. (Debilitating cramps where I couldn’t even move to stretch them out.) Even drinking electrolyte mixes on the bike didn’t seem to help. I wonder if the calcium leaking from my muscles also caused some of these cramps.
Glad to hear you are now “enjoying” the trainer. I’m sure you’ll be so glad you logged all those hours on it when it comes time to hammer out a real ride if spring ever arrives.
Dana