Comrades Classic: The Science Of Sport analyzes Leonid Shvetsov

The Science of Sport reports

Five hours, 21 minutes for 89 km. That’s a pace of 3 minutes 36 second per km (or 5:48 per mile for our American readers). It’s a 36 minute 10-km race, run nine consecutive times! That would give a guy a place in the top 30 or so of most smaller road races, certainly around South Africa, and it’s remarkable only because it’s just so fast. But what of the physiology?

Well, Shvetsov is a sub 2:10 Marathon runner, so he has a speed pedigree that can’t be questioned. So physiologically, his performance is best looked at in terms of his marathon time, and saying that to run Comrades, he has to run back-to-back marathons in 2:32, with a short 5km to finish! Now, when you have a 2:10 marathon best, running 2:32 means you’re running about 16% slower than your best pace for the same distance.

And that 16% is critical. The key thing about the elite runner is not necessarily that they have a higher top speed, but that they can sustain a higher percentage of this than most other runners. So this performance is remarkable because it represents a sub-maximal effort that is so close to maximal that no one else in the history of the race has been able to match it. An example from the world of cycling is Miguel Indurain – he had a peak power output (this is the ‘maximum’ power output as measured in a specific lab test) of about 520 W, yet his world one hour record was averaged at 495 W! That means he’s gone at 95% of maximum for an hour. We do a lot of research on cyclists doing 40 km time-trials (also about one hour long), and most guys ride at between 70 and 80%. That’s the difference between a 5:20 for Comrades and 6 hours. Or between a 2:30 for a marathon compared to 3 hours, or 3:30 to 4, and so on.

So back to Shvetsov, what he demonstrated is a remarkable ability to run close to maximum speeds for very long periods. Most runners can’t do this, and they will go through the marathon quite substantially more slowly that the elite runner.

Now, it’s worth looking at what the adaptations are that allow this to happen, asking WHY can he do it?

The first is metabolic, or energy related. The elite athletes have a superior ability to use fat as a fuel. Very briefly, you will use predominantly carbohydrate (glycogen and glucose) and fat for energy during exercise. The problem is that the carbohydrate stores are limited, and so you have to rely on fat. As soon as you run out of carbs, you “bonk” – this is the lay term from becoming hypoglycaemic, when your blood sugar levels drop too low. Running on once this has happened is near impossible, so it’s critical to keep the blood glucose levels up. You do this by eating and drinking during the run. But back to Shvetsov, the latest scientific evidence has shown that the brain is able to pick up how much carbohydrate you are using, and then calculate whether you are in any danger of running out before the end of exercise. So let’s talk hypothetically – at the 10km mark of the Comrades (or any marathon, for that matter), your brain knows exactly how much carbohydrate is left, and also how quickly it’s being used up. A quick calculation, and it works out that at the current rate, you can go for another 34 km before running out. If you are running a marathon, that’s fine, you’d reach 44 km, and so you’d finish. But if it works out that you’d last another 20 km, then you have a problem. And what it does is slow you down so that you don’t run into trouble. So your pace right from the start is determined by an anticipatory calculation of what energy you have available, weighed up against how much you are using.

So for Shvetsov, Remarkable physiological adaptation number 1 is that his body is using fat at such high rates that he doesn’t have this danger of running out of glycogen. Most guys, running at 3:36/km, will be using glycogen heavily, but not him. That comes from many miles of endurance training – a well trained endurance runner is super-enabled to use fat as fuel.

The second adaptation is also metabolic, and has to do with lactate. Right from the beginning, let us repeat that lactate does not cause fatigue, nor does it cause muscle pain, as is so often thought. But it is associated with changes in muscle pH, and so may be involved in a very complex process of fatigue, but for high intensity exercise only. For an event like Comrades or marathons, lactate has another very important function – it is a source of energy.

What happens is that lactate gets formed in the muscle, is released into the blood, and is that taken out the blood by other muscle and used as energy! So far from being a poison, it’s actually a critical source of energy (those of you in SA can read my article “Turbo Charged” in the June Runner’s World). An elite runner, like Shvetsov, is better able to use lactate as a source of energy because he will have a greater capacity to take it into the muscle and then use it – more enzymes, and fancy molecules called transporter proteins. This is adaptation number 2.

The third adaptation is muscular. The down run of Comrades is unique because of the massive demands it makes of the muscles. They have to perform thousands of contractions that we call ‘eccentric’, which means the muscles lengthen as they contract (weird, I know!). But these eccentric contractions do a great deal of damage to muscles, causing tiny tears in the fiber, and this is ultimately what makes runners so stiff after running. You will have seen the not so fast guys shuffling in at the end of the race – that’s because the muscle has taken so much damage that it loses all its shock absorbing properties, and can simply not take the load any longer.

But not Shvetsov – he bounced from the start to the finish, and this is a remarkable adaptation that is difficult to explain. It means he has unbelievable strength, for one thing, because the muscle withstands such severe loading for so long better than in any of the other 9000 runners. That comes from a lot of strength work (you could see that he was strong in the legs) and also from massive mileage, great recovery and, I suspect, very specific training sessions that were designed to improve this ability. Research has shown for example, that repeated downhill running reduces the amount of muscle damage in future bouts, so the muscle is getting stronger.

So that’s the three main adaptations, in a nutshell. All must be unique to enable the performance you saw. All are the result of training, lots of it, and very specific types of training. The body can be trained, for example, to burn more fat through many miles of long runs, and you can play around with the energy supply to manipulate this further. You can also train the ability to use lactate, and the ability to withstand downhill running contractions. The one thing that must be pointed out here though is that few people can actually run the miles required to achieve these adaptations. So you have to a biomechanically perfect runners – any dodgy running form will be exposed pretty quickly once you do the high weekly miles. We’re talking 200km plus weeks, for months of the year!

Next time, we’ll look at an entirely different set of physiological attributes, when we discuss Calie Beneke, a 70 year-old with an 8-hour Comrades (that’s a 3h30 marathon, folks!)