This is the first of three posts about my journey into the strange and wonderful world of energy systems:
- this first post is about aerobic respiration;
- the second post will be about anaerobic respiration; and
- the final post will be about the creatine phosphate system.
These three energy systems are the main three that I am studying for my personal training qualification. In fact, there is a fourth system, which is the ATP stored in the muscles. However, this is very small and only addresses the first couple of seconds of a movement.
For an interelation of the four energy systems, see this article (the graph about halfway down the page is informative).
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What is aerobic respiration?
Aerobic respiration is the energy pathway that supports long-duration exercise.
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What fuels aerobic respiration?
As we saw in the nutrition series, aerobic respiration can be fueled in three ways:
- Carbohydrate: glucose from carbohydrate directly processed by glycolysis, which creates pyruvate. Pyruvate is then used in aerobic respiration through oxidative decarboxylation, the citric acid cycle and the electron transport chain.
- Protein: amino acids that has been subject to gluconeogenesis are then subject to glycolysis, again, creating pyruvate.
- Glycerol: glycerol, which is part of the triglyceride molecule, the form in which fats are transported around the body, can enter the citric acid cycle.
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Glycolysis?
Glycolysis is the splitting of glucose. It’s kind of a preliminary reaction that feeds into both the anaerobic and the aerobic pathways. Glycolysis is an anerobic reaction but don’t let that fool you. It’s not tied to the anaerobic pathway.
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So how does it all hang together?
It’s probably easier to visulise using a picture so here’s a graph to summarise it all again:
Training the aerobic system
Aerobic training is essentially training the body to carry out aerobic respiration at a higher rate. The effects of this training are perceived when the trained athlete is then able to go faster for the same distance, assuming the distance travelled takes more than a couple of minutes.
This is where things get interesting. It’s one of those areas where everyone has an opinion about how best to do it. In fact, it probably justifies the statement my old lecturer at university used to make that “opinions are like armpits. Everyone has two and they generally stink.”
However, having read around the subject a bit, I’vestarted to see a couple of interesting trends. Leaving aside the “fair and balanced” people who try to deduce a middle road, I’ve noticed that there are the reductionists, who focus on the long and slow aspect of training, and there are the iconoclastic modernists, who seem to believe that you can develop aerobic capacity using mainly intervals.
The question is, are either extreme right or is the truth somewhere in the middle?
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The reductionists: go long and slow
Take for example, the superior British time triallist, Michael Hutchinson, who has dominated the UK time trialling scene for many years. You have to bear in mind that Michael isn’t a typical athlete, as he was educated at Cambridge and went on to be an acaedmic in legal studies.
Michael’s thoughts on endurance training, however, are a perfect example of the long-slow reductionist camp. They hold that ultimately you just need to go long and slow for a very long time and eventually you will develop a huge engine capable of great aerobic ability. Michael expounds the point in his own dry way as follows:
“The concept of physical training is a simple one. You subject your body to a physical stress. It adapts to the stress and grows stronger. In short, the more you do it, the better you get. However, for the hundreds of university exercise physiology departments to justify their existence, this simplicity has to be played down.”
“For aerobic endurance events, the basic model usually works like this. You spend a while doing long, slow to moderately paced training. The exact length of ’long’ depends on your boredom threshold as much as anything else.”
“An eminent physiologist recently came up with the notion that a major determinant of cycling ability was simply the number of pedal revolutions you had clocked up in your life. Naturally, this embarassingly simple idea was hushed up.”
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The modernists: intervals are what you need
I’m not going to go into a great amount of detail about interval training here – I have some scope to talk about these later in my series - but good examples of what I mean by the modernists in this context are CrossFit Endurance and Gym Jones. I also have some personal experience to share about swimming training (which was 90% intervals), rowing training for the BIRC (which was 100% intervals) and cycling training (which was 100% long-slow duration).
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Over to you
That’s it for today, I’m afraid, but if you have any thoughts on my reductionist/modernist classification, please let me know. It would be interesting to see whether other people have made the same observation or if I am being overly black and white…
