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Endurance Training Explained: Part 1

before capillarisation

Prior to Endurance Training (Dave Costill PhD)

Somewhere I said that if an idea wasn’t simple enough to be written down on a matchbox, then it was probably too complicated to get across. So, on that premise, my ‘matchbox’ contribution is that the total volume of low-intensity aerobic base training completed before a peak racing season dictates high-intensity anaerobic outcomes as we get towards peak racing. Or, even simpler: Aerobic training defines anaerobic training potential. Or: Steady Quantity defines eventual Intense Quality.

But hold on! Isn’t there constant discussion everywhere about how there’s never really such a thing as totally aerobic or totally anaerobic? Yep- that’s quite correct. However, we as humans need to label everything and put them into their boxes before we can understand what we’re dealing with- so in this case, we have to talk in very black and white terms to ‘frame our conceptual tapestry’ (nice phrase, eh?).

Why Endurance Training?

The whole human body runs on energy derived from food, water, and the air we breathe: Energy is created from glucose, derived in one form or another from long chains of glucose molecules stored as starch (glycogen), or glucose already in the bloodstream from the digestion of foods, or glucose from the reassembly and breakdown of fats and proteins. Glucose can be derived from essential fats (triglycerides) by a breakdown process that cleaves the longer-chain fatty acid molecules into several smaller (glucose) units that can be easily transported across the cell membrane (cell wall) into the internal structures of the cell.The end of the process will always result in a release of energy through the extremely rapid breakdown of high-energy phosphate bonds.

There is ample evidence around to demonstrate that a concerted period of low-intensity training volume results in significant increase in CAPILLARISATION within the trained muscle. There is also ample evidence showing that the body thrives best in a slightly alkali environment, as opposed to slightly acidic. (Think milk versus vinegar, although in fact milk is itself still slightly acidic, to be pedantic). Prolonged high intensity training without due low intensity recovery has been known to elevate ACIDOSIS in the body, which in turn mucks up cell membrane walls, lowers immune response, and mucks up normal fatty acid and carbohydrate metabolism, as well as the highest-energy alactic energy system. So everything will be stuffed, and will need days to recover.(See all the references in the book!) The illustration here comes from Dr Dave Costill’s great book ‘Distance Running’,(1979), and is a cross-section of muscle fibres and capillaries before endurance training. In this view there are only 11 capillaries highlighted in red. In the next section you’ll see how much capillarisation occurs in another biopsy from the same muscle.

‘Synaptogenesis’(the formation of new synaptic connections within the neuromuscular system) and ‘Angiogenesis’ (the budding of tiny new blood vessels which eventually become capillaries or even larger venules and arterioles) are far more likely in an alkali environment. Intense training can promote a powerful stimulus for angiogenesis, however this will only really occur if the whole system is allowed to recover adequately. The same for synaptogenesis. With intense training, and the necessary very easy days to recover, you’ll lose a lot of steady aerobic work time, and all the benefits that come with that background.

There is absolutely no point in doing faster, more intense work until a modicum of essential, basic fitness has been acquired. This basic fitness would include good tendon strength and elasticity, and a highly developed capillary system that literally “irrigates” the muscles with fresh oxygen, glucose, and fatty acids, and transports the byproducts away quickly.

Once this basic fitness has been acquired, it can be increased methodically over a number of weeks by deliberately running ‘solidly’ for up to an hour once or twice a week at a level that can be described as “strong” or ‘high aerobic’. Build up to the hour steadily in increments of a few minutes each time from a starting level of around 20 minutes within a 1 hour run. The body seems to like variety in its aerobic training, so we include longer slower runs and shorter steady runs on varying courses each week as well. These runs are also known as ‘3/4 effort’ runs in Lydiard terminology.They are also known as ‘sub-threshold’ runs because they are not supposed to be anaerobic at all.

After a substantial block of consistent training at mainly aerobic levels, but with regular attention to the ‘strong’ runs, by the end of 8-12 weeks the body will be substantially faster at all aerobic speeds, due to the proven increase in capillary density. Not only has the physical “plumbing supply and waste removal” capacity been increased, right into the very depth of the muscles, but the oxidative enzymes and energy production pathways within the muscle cells will have gone up significantly. Enzymes are substances that can increase the speed of chemical pathways in the body exponentially in some cases. There are enzymes capable of breaking high-energy bonds between molecules and releasing energy as a by-product, and also enzymes that do the reverse, in order to store energy.

There will be proliferation of ‘mitochondria’ in any muscle cells that can utilize oxygen. Mitochondria are the ‘furnaces’ in muscle cells and other organs that are responsible for mixing these enzymes and fuels in the presence of oxygen to deliver rapid energy by breaking phosphate bonds in the ATP molecule (adenosine tri-phosphate).

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keith@drkeith.com.au