Comment by kirse | Hacker News Reader

Comment by kirse | Hacker News Reader

As someone who has run everything from 10 miles down to the 100m for the past 15 years, there are two types of barriers of fatigue when at maximal performance.

The first barrier is the pain felt because you're running at max performance. This is all mental, and you learn to love it. The mental barrier grows exponentially more difficult to fight as you get closer to...

The second barrier. The true hard limit, as defined by your body's innate physical capacity to perform. At this point you've managed to push past the mental barrier and used up every ounce of energy. It's typically marked by a visible decrease in performance aka "hitting the wall". I've done it before, and there is no amount of mental convincing that will get the body moving when there is no more fuel in the tank. This shutdown might be a protective function of the brain (as a physical organ) looking to ensure it can still function, but there really is no physical capacity left to continue at speed even if the will is there.

Any true athlete intuitively knows from their training when that second wall is approaching and will time it as best as possible so that they get as close to it as possible just as they finish their performance (hence running faster at the end). This is much more evident in endurance events where blowing past the anaerobic threshold too early is disaster for the competitor.

One of the best events to watch athletes hit the second wall is the 800m.

Except that the point of this article is that this "second wall" is in the brain, and not in the muscles.

This article is really poorly written from this standpoint, because they claim to argue that peak performance is rooted in unconscious mental processes, but then it goes on to say this:

While the fMRI results of the Birmingham experiment were promising, they did not come from subjects who were actually exercising. Because fMRI requires subjects to keep their heads perfectly still, it’s not clear how the technique can be effectively applied to bodies in motion.

In this study of cyclists who are clearly still fighting the first barrier (mental), it notes that giving them an energy drink is a boost regardless of whats in it. All this reinforces is that athletic performance is truly mind over body until the body has nothing left to give.

In addition, the article interchanges "mind" and "brain" throughout, which only serves to confuse whether its talking about mental willpower or the brain as an organ (which is entirely physical) functioning to protect itself.

Is such a distinction even useful if the "second wall" is what prevents the body from sustaining severe or permanent injury or worse? I mean, sure the brain may be limiting performance, but if all you end up with my removing the limit is a small performance gain at the expense of death then the "mental" limit is hardly distinguishable from an actual physical one.

There are really two ways in which runners "hit the wall". One is when lactic acid builds up in muscles causing not only pain but decreased performance. This is due to muscles using anaerobic metabolism when there is not enough oxygen being brought to them. This is typically what you'll feel at the end of an 800m race.

The second type of "wall" that can be hit is when the body runs out of glycogen and has to start burning other things for fuel. This is what you will most likely be feeling at the end of a marathon.

In no case do I believe that "Runners are often at their fastest at the end of a race, when they should be the most tired." In fact I'll call bullshit on that one.

Lactic acid doesn't cause pain or decreased performance: http://www.nytimes.com/2006/05/16/health/nutrition/16run.htm...

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