Tuesday, 27 November 2018

You need to slow down

This blog has been historically focused on technical topics in areas related to Real Time Communications, but I'm taking the liberty to digress a little.

I've been reading recently about the dynamics of performance in running.

I'm just an amateur runner, and I always train (and race) alone, so I felt the need to make it more interesting than just reading training tables. I've been studying what is it that limits performance. "Train more", unfortunately, not only doesn't always work, but needs to take into account injuries, and overtraining in general.

One of the first concepts that struck me is that it's been proven that fatigue, and the consequential slow down, does not mean that the body is unable to continue with that effort. What's behind slowing down is a sort of protective mechanism in our nervous system, which wants to prevent the body to reach exhaustion.

Our nervous system is constantly getting feedback signals from the body, including the perception of adverse weather conditions, and computing for how longer the current effort can be sustained. Even knowing how long is left to run is a form of external feedback.

When this computation detects that the effort is too high, the nervous system takes control and doesn't fire as many muscle fibres as the athlete wants to. The athlete thinks the muscles can't continue to work at that level, but in reality they are entering a protective status. Without that, people could literally run until body exhaustion or even death.

I find this fascinating. Evolution has given us a sophisticated algorithm aimed to prevent body exhaustion by generating fatigue symptoms and consequently reduce the actual effort.

What's also fascinating is that it seems this system can be "tricked". One way of doing is by training. Training is a way of educating your nervous system that a certain effort is OK. "There's no need to shut me down, brain, I know what I'm doing. I did that thousands of times in my training sessions."
So while the body adapts to the stress of training, the nervous system too becomes more familiar with that stress, and gives up a little.

Another way of tricking that system is by providing false external feedback. It seems that if you get false information about elements like the air temperature, or even the remaining time in your training session or race, then the nervous system acts accordingly. If it believes it's not as hot as it is, it will not intervene to shut the muscle fibre activation.

Similarly, if the athlete thinks the race is close to the end, the nervous system will allow a prolonged effort. This is why elite marathoners, who clearly haven't underperformed for the first 40 km, can run the last 2 km even faster.

Of course, all these tricks have limits, and the improvements that can be tricked are in the order of small percentages. But still this shows the importance of external feedback.

This is properly explained by Steve Magness in his "Science of running" book. I then read another book from this author, "Peak performance". To be perfectly honest, I was expecting something strictly related to endurance sport, but in this second case the concept of performance was wider.

There seems though to be an analogy between the shutting down of muscle fibres from the nervous system during running, and something that happens behind a desk and is more widely known: mental burnout. From this point of view, mental burnout can be seen as a way of saying "You can't keep going at this (perceived) level of effort. You need to sleep, hydrate, rest, but you keep working. I'm going to take control and shut you down.".

As I'm making my own little experiments, in the future I'd like to write more about this, and in particular about the relationship between effort and rest. 

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