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The final day of athletics competition in Beijing brings with it one of our most anticipated races of the Games - the Men's 800m event. As we wrote yesterday, the event has already thrown up some huge surprises, because three of the big favourites failed to even qualify for the final! Yuriy Borzakovskiy Mbulaeni Mulaudzi, and Abubaker Kaki Kamis all failed to advance from their semifinals in what must be one of the most open, competitive and unpredictable events in athletics.
The race without the favourites should be fascinating, and any one of the eight athletes could win it. Most impressive in qualifying has been Wilfred Bungei (who has the experience to boot), and so I'd probably bet on him if forced to. But really, any one of the other seven could beat him - look for Kirwa Yego (also of Kenya) to be competitive, and for a "dark-horse", keep an eye on Gary Reed of Canada.
Today's post is not so much an event preview, however, as it is an examination of the fascinating physiology of the event. So here is the physiology of 800m running, which will hopefully provide some more insight on the events that will unfold in Beijing tomorrow.
A tactical game: Pacing and strategy as vital as physiology
The 800m distance is fascinating because it straddles the divide between what people usually refer to as "sprinting" and "middle distance" running. To some, it is the first of the middle distance events, whereas to others, it's the last of the sprints. Of course, using such jargon can pose challenges, but generally, when people refer to a sprint, they refer to an event where the athlete goes 'flat out'. This is of course never true, because even in a 200m race, there is some pacing, as evidenced by people who go out a little too fast and end up faltering in the final 40 to 50m! By failing to pace herself properly, Sanya Richards demonstrated the value of pacing in the 400m event, when she got it wrong and was reeled in by two athletes in the final earlier this week in Beijing. So pacing is certainly as vital in sprints as in middle distance races, which brings us to an analysis of the 800m event.
Coaches (and physiologists) have often spoken of an aerobic-anaerobic divide for different events, and they often refer to the 800m distance as being a 50% split for each. That is, they say that approximately 50% of the energy comes from aerobic sources, 50% from anaerobic. This is a contentious issue in itself, one that I would argue with, as recent evidence suggests there is no black and white split between the energy sources. It's more likely, based on recent work, that the aerobic component is far larger - even in 400m running, it's almost 50-50.
What is optimal pacing?
It is often said that the ideal way to run an endurance race is to aim for what are called 'even splits'. In other words, the first half and second half should be run in the same time. If you are a 10km runner, for example, the ideal strategy seems to be to run even pace the whole way. An underperformance happens when you either start too fast and slow down (called a positive split – the first half will be faster) or you finish very fast, running the second half faster than the first (called a negative split). For most recreational runners, aiming for a negative split is probably the prudent approach, recommended as a safety first option.
To fully appreciate pacing strategies, you have to look at a range of different events, and so we'll look briefly at the track events from 800m upwards. We'll do it in reverse order, and work our way backwards to the 800m event.
10 000m distance – even pace is the way to go, with a fast finish
In the men's 10000m distance, 34 world records have been set in the modern era. It's quite clear from the graph that on average, the race is even paced, with a fast start, more consistent period in the middle, and the final kilometer is fastest. In fact, in 33 out of the 34 world records, the final kilometer was the fastest of the race. What this means, practically, is that even the elite have left themselves something in reserve for the final kilometer. You may be thinking that this indicates that the athletes are not performing maximally, because surely, if you have enough for a sprint at the end, you might have been able to go quicker in the middle part? And you'd probably be right, and that's one of the big unknowns in exercise science - what does this reserve mean, and how can it be accessed sooner (or more fully?)
We did discuss this issue in our series on Fatigue earlier this year, and you might spend some time looking at that for futher insights. The very summarized version is that the brain prevents the runner from ever fully accessing muslce motor units until the end of the bout, when the "danger" has passed. The "sprint" at the end is the manifestation of that reserve, but it's not a simple matter of accessing sooner, because it serves an important regulatory function as it protects against possible damage during exercise. The great atheltes go closer to the "limit" than others, it's part (though not all) of their advantage.
Men's 5000m – similar to the 10000m, the pace is even, with a final kilometer kick
There have been 32 world records in the 5000m event, and the pacing is very similar to that of the 10000m. The first and final kilometers are faster than the middle three kilometers, which again suggests that the middle kilometers are somewhat 'conservative'. The final kilometer has been fastest in 21 of the 32 world records. In the other 11, it has been the first kilometer that is fastest. So for those wondering about tactics, they are certainly in play, but they have never once produced a fastest kilometer in the middle of a 5km race.
Men's 1 mile – a much more even pace
The men's mile event begins to get down into the range where speeding up at the end is a lot more difficult to do. On average, the final lap is run in the same speed as the first lap. In fact, in more than half the world records set, the first lap is actually faster.
There is still a drop in pace in the middle part of the race, but the overall strategy is even, in contrast to the longer races, where the fast final kilometer ensures that the second half is usually faster. So here, in the even that lasts about 4 minutes, we see a subtle change, which has physiological relevance. Because the even pace in the mile suggests we are getting down to the point where speeding up at the end is becoming increasingly difficult for optimal performance. Which brings us to the 800m race…
800 m – it's not possible to run optimal times with a faster second lap
In the 800m event, 26 world records have been set. The graph below shows the average lap times in these 26 races. It's immediately clear that the second half is quite a lot slower than the first. Some of you may be thinking, hang on a moment, what about the 200m splits? Unfortunately, they are not available for the 26 world records, but in the ones they are available, they follow the same pattern – the first 200m is fastest, followed by the second, and the pace gets slower and slower.
So this is a departure from what we've seen before – suddenly, speeding up at the end of an 800m doesn't happen. In fact, in the 26 world records, the second lap has only been faster than the first on ONLY two occasions. Therefore, a world record seems to require that you run a fast first lap, and then hang on in the second, but speeding up does not appear to be an option.
Some of you may now be questioning this statement. Among the biggest challenges would be the assumption that you're seeing 'optimal performances'. And of course, this is true. If a guy goes out and run 1:46, who is to say that is not optimal? Perhaps it is. However, I still maintain that with this pacing strategy observed in 24 out of 26 world records, the best way to run the race is to run the first lap faster than the second. On average, the difference is 2 seconds. This means a first lap of 50 seconds would be followed by a second lap of 52 seconds.
What is even more interesting is that the two fastest second lap times ever achieved in 800 m world record performances were run in 1972 and 1966 respectively. The graph below shows the lap times from all the world records, and if you look at the panel on the right, you will see that the second lap time of a world record performance has not improved in 35 years, since Dave Wottle broke the world record with a time of 1:44.3 (min:s) and a second lap of 51.40 seconds in 1972.
The current world record holder, Wilson Kipketer, has broken the world record on three occasions, with second lap times of 52.12, 52.90 and 51.80 seconds. Therefore, a 3.2 second reduction in the world record in the 800 m event between 1966 and 1997, from 1:44.3 to 1:41.11, has been achieved by running the first lap significantly faster, rather than an improved ability to increase running speed on the second lap.
The Figure below shows the lap times for the 26 world records in the 800m event. The left panel is the first lap, the right panel is the second lap
Another interesting fact is that the second lap is slower even in the Olympic Games, where the first lap is often tactical and slow. In other words, a slow, tactical first lap is still followed by a slower (on average) second lap, despite your perceptions that the athletes are "sprinting" for the line! The average first lap in the Olympic Games finals is 52.8 seconds and the second lap is 53.4 seconds.
What this suggests is that the ability to run faster during the second lap of an 800 m is limited, and so the optimal pacing strategy may consist of a faster start followed by a relatively slower second lap. I'm going to go out on a limb here and say that if you are an 800m athlete, or you are coaching an 800m athlete, if you want that athlete to run their best, you have to plan for a second lap that is about 2 to 3 seconds slower than the first. So, if the goal is 2 minutes, it's not good enough to aim for a first lap of 60 seconds. It has to be 58, because if your athlete is going maximally, then he should slow down to a 61 something on the second lap, giving him a final time just under 2 minutes.
Similarly, if you want to break the world record, forget about running the second lap in 51 seconds. It's not going to happen. Therefore, you must plan for a second lap of 52 seconds, which means the first lap must be 49 seconds, or faster. This is also an indication of the sort of speed needed to challenge Kipketer's world record – you have to be able to run a 400m in 48.5 seconds as part of an 800m race. Your basic 400m speed therefore needs to be down in the 45's, maybe 46 seconds (but that starts cutting it fine).
So looking ahead to the 800m final…
The 800m final is more likely to be a tactical affair, unless someone has decided that his best shot is to follow in the Women's champion's (Palema Jelimo) footsteps and go as fast as possible from the gun. Jelimo found a willing ally in Jepkosgei, which is unlikely in the men's race. So therefore, a slightly slower race might be expected, and this means the race will be roughly evenly-paced.
I suspect the first lap will be run in about 52 seconds (wild guess), meaning that the second lap will probably be run in about 52.5 seconds. You'll note that this is still a slower second lap, which is really interesting from a physiological point of view – why can you speed up in a 1500m, 5000m and 10000m race, but not the 800m race? Is it a different type of fatigue? Again, I've said this before, but it's worth repeating – we don't really know what causes this, and if anyone tells you they do, they're lying! It's quite a mystery.
But for the race, it means that the athlete who has the ability to maintain speed is likely to come out on top. In the past, the former Olympic Champion, Yuriy Borsaikovsky, was the master of the "fast finish". I hope that by reading this, you now appreciate that this is not 100% correct – the truth is that he wasn't necessarily the fastest finisher, but rather that he was the least slowing finisher! So his strategy was to hang back over the first 400m, which added about 1 second to his lap time. But he was able to maintain a pace on the second lap that was much closer to the first lap, and appeared to have an incredible finish. I don't have the data, but I would suspect that in his major victories, he ran roughly even splits (between 0 and + 0/5 s), when the rest of the field were running a positive of at least 1 to 2 seconds.
Of course, when Borzakovskiy or anyone else goes out for a fast time, he has to run the first lap in 49 seconds - the speed is "limited" on that second lap and simply can't be much faster than a 52.
Anyway, returning to Beijing, the race will come down to the final 300m, where tactics will be incredibly important. As will speed-endurance – the ability to sustain a fast pace on the second lap, running as close to even splits as possible is a unique physiological ability. That is what makes the race so unpredictable. We saw the fastest man in the world (Kaki Kamis) "disappear" from the race in his semi-final, and so calling it will be difficult. But I'd guess that Bungei comes through, winning perhaps from Reed and Kirwa Yego. Then again, I thought Kaki Kamis and Borzakovskiy would be racing for gold!
Enjoy!
Ross
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