Pacing physiology and the limit to performance: A #fourminute mull

15 Feb 2018 Posted by

Here’s my latest #fourminutemull, and it’s a trip down memory lane, because it covers the physiology of pacing strategy and the limit of human performance, which is the subject I studied for my PhD.

The bit at the end is something I always found enormously interesting. Having analysed the pacing strategy of the middle and long distance track world records, I never got round to this “era analysis” (watch the video) in a scientific paper, but it was one of the more interesting things I noted in that time.

Why does it happen – new athletes (African vs European), commercialization of the sport leading to structured world records with pace-setters, awareness, necessity.  All options, but I thought an interesting phenomenon and I hope you’ll enjoy it too!


The Four Minute Mull: Pacing physiology and theoretical performance limit


Other thoughts and some reading links

I’ve since all but left this field alone, and now study mostly concussion and injury epidemiology.  That’s partly because the pacing world feels like it’s treading water a little (with one or two notable exceptions – see below).  When I finished my PhD in 2006, it had reached the point that without being able to look into the brain during dynamic exercise, we were doing the equivalent of painting the walls of a house without ever going inside!

However, an even bigger issue, I felt, was that the pacing strategy/physiology regulation field is cannibalizing itself with academics trying to slap new labels on old concepts for reasons only they know.  Not much of this stuff, including my own contribution, is truly novel to coaches and people who are immersed in the sport.  It’s often ivory tower stuff.

Also, the desire to be acclaimed for proposing a model gets in the way of true integrated progress.  I say this because towards the end of my PhD, I realized that we too were doing this, and overlooking (on purpose) some of the outstanding work that others were doing in this field all because we were trying so hard to push a “model” for our own gain that we failed to see the whole picture (this is partly why I did not use the term “Central Governor” in the 90,000 words of my PhD thesis).  I may forever feel like I’m atoning for this myopic start.  Some currently in the field are taking it to new heights, though, and it is, in my opinion, toxic and unpleasant.  I’m glad to have handed in my badge and gun (mostly, anyway. I did a little guest ‘patrol’ with Zig St Clair Gibson last year!).

Those who follow or have followed my writing for a while will recognize this as a manifestation of what I’d later call “pixelation” in the context of anti-doping and performance evaluation, but it was the same thing applied to pacing.  We were so “territorial” and possessive over “our model” that we overlooked some outstanding work by researchers like Markus Amann, Romain Meeusen, Les Ansley, Carston Lundby etc.

The same is happening now.  It was a relief for me to leave this world behind and get stuck into biomechanics and then concussion and injuries.   That said, thanks to Zig St Clair Gibson, I did help co-write one more theoretical paper on the regulation of physiology and performance with him and Jeroen Swart (who also did a whole bunch of stuff to advance the regulation concepts that I mentioned above – here’s one of those important articles, this one on certainty of the endpoint and RPE regulation).

The paper with Zig and Jeroen was published last year, and we called it the “Integrative governor”, and you can read that paper here.

In any event, I mention a lot of papers in the video, and so I wanted to use this post to provide links to some of those papers, and others you may find interesting.


Papers mentioned in the video

The two reviews that I mentioned were published in the British Journal of Sports Medicine.  These were basically the first and final chapters of my PhD thesis.

  1.  Review of pacing physiology
  2. The anticipatory regulation of exercise performance, with perceived exertion at the center of performance and physiological regulation

Then the paper that analyzed the world records in track running can be found here.


Recommended reads

Markus Ammann’s group has done a bunch of studies on fentanyl and the inhibition of afferent feedback.  This one in particular was an excellent study, showing that if you block that afferent feedback from the muscles, the pacing strategy goes haywire.  The guys went off like a house on fire, and then the house burns down in the second half!

The result is that the cyclist develops excessive peripheral fatigue because any ‘inhibition’ (I prefer the word ‘regulation’, maybe) is removed when feedback is stopped.  This study fits perfectly with the theory for anticipatory regulation, with the degree of peripheral fatigue being one of the regulated variables.

Another one from Ammann is this, which also helped establish that the regulation of pacing strategy (that is, central motor command) is achieved at least in part to prevent excessive peripheral fatigue.  I probably need to do a #fourminutemull on just these two studies.  One for the future.

The group of Les Ansley, this time led by Thomas, did a cracking study where they showed that the nature of fatigue was contextual, dependent on the intensity of the exercise (which is in turn set by its duration).  That is, when you do short duration, high intensity exercise, you get a greater degree of peripheral fatigue, and when you do longer duration exercise, central fatigue is predominant.  I really liked this study – it was elegant and found a good outcome.  The mechanisms are obviously complex, but this is a good study showing how fatigue is not all one thing or another, and that’s something that gets lost on this journey.

The people doing the cool stuff now, should you wish to follow them, are:

Dominic Micklewright – aka @athletefatigue

Carl Foster – the godfather of pacing (and many other things). He’s not on Twitter, but here’s one of his big pacing review articles, from way back in 1994.  He was ahead of the curve. I was most fortunate to have Carl be one of my PhD Examiners.

Jos de Koning – also a PhD examiner of mine.  Here’s one of his great pacing review articles

Florentina Hettinga – a student of Jos’, she unsurprisingly does very good technical pacing analysis.  She is on Twitter, you can find her @FJHettinga

The afore-mentioned Zig St Clair Gibson, with whom I wrote that Integrative Governor paper last year, and who thinks differently about these issues, in a good way.  Here’s one you might enjoy, on why athletes collapse.

Like me, Jeroen has moved on to other research areas, but some of his stuff from his own PhD studies is well worth a read.  I already gave the link to a paper on exercising with reserve, here’s one where a central nervous system drug affected RPE and performance to further show the reserve concept.

That’s all for now. I am sure more #fourminutemulls on these topics are in store!


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