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 Lactic Acid Is Not Muscles' Foe, It's Fuel
Submitted by Rickshaw :: Wed Jun 21, 2006 4:54 pm
Is lactic acid a friend or foe? Most athletes believe its buildup in the muscles causes pain and fatigue, but a recent New York Times article says we've got it all wrong. According to the author, lactic acid isn't your muscles' foe, but its fuel. Muscles make it deliberately, producing it from glucose, and they burn it to obtain energy. The idea that lactic acid is bad has its roots in century-old experiments with frog legs, and was never strongly challenged. Says George A. Brooks, biology professor at UC Berkeley, "It's one of the classic mistakes in the history of science." What do you think?


Rickshaw
Runworks 2005 5M Racer
San Francisco, CA
Joined: 26 Nov 2004
Posts: 1157

Re: Lactic Acid Is Not Muscles' Foe, It's Fuel Posted: Thu Jun 22, 2006 2:13 pm 

An interesting article, but I think it's misleading. So far as I'm aware, there's no "classic mistake" here, and most people are already aware that lactic acid functions as described in the article.

Maybe it's a question of your point of view. The conventional point of view says that pushing beyond your aerobic threshold causes a build-up of lactic acid, which causes fatigue and is "bad". But from my recollection of biology, lactic acid is a normal part of anaerobic cell energy production, like the article said. However, anaerobic energy production is a lot less efficient than aerobic energy production, so the body only does it when there's not enough oxygen to meet the demand.

So maybe it's better to say that lactic acid is a symptom of physical distress, rather than a cause. Either way, knowing your aerobic threshold and training at it is still useful, and the measurement of lactic acid levels to determine the threshold pace still makes sense.


aquastang

Marshalltown, IA
Joined: 12 Jun 2005
Posts: 2

Re: Lactic Acid Is Not Muscles' Foe, It's Fuel Posted: Fri Jul 28, 2006 11:46 pm 

Good point. Maybe the masses that read the New York Times aren't aware of this, but I think most well read runners are. In my mind, the threshold is just as you say it is - an indicator. Our body telling us that it can no longer balance the output and subsequent reprocessing of the lactic acid being produced on the cellular level.

In fact, when I was at USATF Level 1 school a 10 years ago, we discussed this idea. The instructor that I had talked about developing mitochondrial density throughout the body. This got me thinking and I have found a few articles and abstracts lately that talk about a "shuttle system" where the lactate is actually absorbed back into the mitochondria. My instructor at the time was absolutely positive that if we develop mitochondria in the upper body as well, then there will be a place for the blood to ship it to besides muscles, live, heart. Then it can be reprocessed as a fuel. He had his athletes do 20 minutes every other day on an armbike setup to work the upper body aerobically.

I tend to think that this actually works fairly well. While I am no scientist, and the terminology gets all tangled up inside my brain, my athletes have had great success with adding things like treading water with arms only or doing arms only on an armbike for 20 minutes at least a couple of times a week. This acts as part of our cool-down. The athletes like it and we even play water polo for 20 minutes, or at least until the dunking starts getting out of hand!


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