The Ongoing Myth of Lactic Acid

Well, the while the triathlon season is over for me, the racing season all together has not yet come to a close.  Even so, I thought it would be a good idea to start a lot of ideas on training principles, as well as updates on my own training for next year.  In an odd way, ever since the beginning of this triathlon season back in May, I've been looking forward to the twilight of this season so I could start training for the next.  It is a funny truth that one finds out what he or she should have been working on once the season starts.  Unfortunately, the seemingly endless cycle of buildup and taper for races that occur anywhere from every weekend to every other weekend during the season make it virtually impossible to correct these discovered inadequacies.  Simply put:  You don't find out until it's too late.

First, I should preface this by saying that, since the beginnings of my endurance sports career, I have had a keen interest in physiology, exercise science and nutrition as it applies to exercise.  When the day comes that I end up going to back to school, I feel like it would take a lot for me to not pursue these courses of study as they are infinitely interesting and they would allow me to continue to play a role in these sports.

Back in early February, I was having a post-swim coffee and a read of the New York Times at Starbucks before heading off to work.  On the front of the Science section of the paper, I noticed a headline that said something to the effect of, "Scientists believe to have discovered the cause of muscle fatigue".  Naturally, I was a little mystified.  Regardless of the overall awareness of the general public towards this issue, hadn't we endurance athletes been aware that lactic acid is the cause of muscle fatigue for quite some time.  After all, any training article I have read in magazines from Triathlete or Bicycling, to legendary books such as The Cyclists Training Bible (by a certified Level 1 Cycling coach) have unanimously pointed to this as undeniable fact.

But of course, I read the article fully expecting to read, yet again, about lactic acid.  Much to my surprise, within the first paragraph or two, the article very matter-of-factly stated that lactic acid as the cause of muscle fatigue had been dismissed years ago and that it was only ever theory at best.  Needless to say, I was now glued to the article.  It went on to point out that scientists were now fairly certain that they had ascertained the cause.

Apparently calcium in muscle cells is largely responsible for their contractions.  In studies involving mice, scientists found that, after prolonged muscular repetition, a certain amount of calcium "leaks" out of cells, thereby weakening the contractions.  This seemed to make sense to me, but I was still shocked that lactic acid as the cause had been dismissed for years.

The next day, I called a good friend of mine who is a med student and avid cyclist (I rode with him on the Pitt Cycling team back in the day).  I was thinking I was about to spring some ground-breaking news on him, but when I told him about the article, he reacted by saying that, yes people have known that lactic acid is not the cause of muscle fatigue for years.  I told him the findings about calcium leaking out of cells and he said that this seemed plausible.  

So why is it then, that cycling and triathlon coaches, as well as every article I have read since still attributes muscle fatigue to lactic acid buildup?  Perhaps it is not so important because it is the training principle that it produces that is more important than the particular fact.  What I mean is, whether they are called lactic threshold intervals or calcium intervals, the overall goal remains the same:  to increase the body's ability to withstand prolonged activity without tiring.

Even so, I think it is the responsibility of these professionals to relay the most accurate information possible to the athlete and stop furthering theories that have been dismissed years ago.  Training for these sports is difficult and incredibly time-consuming and, with the presence of popular article-writing coaches syndicated across many magazines and websites, we as athletes should not have to also take out a subscriptions to sports science magazines to get to the bottom of these important issues.  

Well, that was a sufficient amount of thinking for the morning, I believe.  Time to head out for a bike/run brick.  Love to hear any comments or reactions if you have them!

Cheers.