London Marathon 2020: Kosgei, Hall, Chepng’etich, Kitata, Kipchumba, Kipchoge

What a joy to watch a marathon again. Let’s just dive right in and look at the different movement strategies the runners used and how this related to their performances.

As interesting as it is to watch any individual athlete, it’s in comparing athletes that you really see how they’re running. Brigid Kosgei and Ruth Chepng’etich running side by side for mile after mile provided ample opportunity.

Here’s the highlights video:


The basics of their form are the same: forward lean, hands close to the chest, good core action, knees bent and legs supple at footstrike… but the difference in their heads is striking and significant.

Compare the head position of Kosgei and Chepng'etich

Chepng’etich’s head is farther forward for much of the race, though the two women are leaning forward roughly the same amount.

If you’ve been reading my blog for a while you know the head isn’t the cherry on top of the sundae, it’s the kite while the rest of the body is the string trailing after it.

A small difference in the relationship between the head and the rest of the runner means a fundamental difference in muscular work and movement strategy.

The difference between Kosgei and Chepng’etich isn’t the difference between right and wrong, it’s simply a different technical choice, and I saw this difference more than once across the women’s and men’s races, so let’s dig into it.

A deeply forward head like Chepng’etich’s is part of an excellent forward lean. While this lean does not produce “free energy” generated by falling as some people argue, it does mean your dynamic balance is farther from vertical, and this includes an anteriorly tilted pelvis that permits a longer stride without demanding as much hip joint extension, and generated with less effort. More about that below, but for now suffice it to say it’s essentially an economical movement choice.

Brigid Kosgei used to have a similar lean to Chepng’etich but her form changed significantly going into the Chicago marathon last year, where she set the new world record. I speculated this had to do with her change of footwear. Obviously it’s not a universal effect of the footwear since it looks like Chepng’etich is wearing the same shoes, but it’s well known at this point that different runners respond differently to the same footwear and orthotics.

Kosgei’s new form uses her extensor muscles more. Her head is a little farther back, and when she accelerates to pull away from Chepng’etich late in the race this becomes more pronounced, demonstrating her increased extensor use (especially glutes) for acceleration.

You can see this in Kosgei on the right. The camera angle makes it look like she’s almost upright, which is not true when seen from the side. But the difference between the two women is accurate.

Chepng'etich and Kosgei late in the race

The success of this running form strategy depends on fitness, fuel, and conditions. It appears to use more energy and make acceleration easier, but you have to have enough energy available to sustain it. Kosgei clearly did.

Kosgei’s movement strategy is similar in some ways to Eliud Kipchoge’s.  Though he doesn’t use his extensors as much as she does, and her narrow gait involves a pelvis movement that couldn’t be more different from his, he always organizes himself to push very actively away from the ground and keep high tonus in his posterior chain.

Take a look at the men:

Obviously in this race, Kipchoge didn’t have the resources he has always had in the past to make his movement strategy work for him. Though he looked good at the beginning, cutting the air like a knife in that special way he does, I started to notice as he ran next to Kipchumba that his stride rate was significantly higher, a vigorous snap to the forward movement of each thigh. This meant a shorter stride length–very visible when the camera pulled back and unusual for Kipchoge.

The comparison with Kipchumba was as interesting as the one between Kosgei and Chepng’etich. Kipchoge has always used the frontal plane more than the transverse plane in his form–the distance running version of Usain Bolt.

Kipchumba has the opposite strategy, with much more transverse plane rotation of his upper body and pelvis. This gives his gait a smooth, rolling quality. As with Chepng’etich’s forward head strategy, it creates a longer stride  without requiring so much power. Starting around 0:33 in the highlights video you can see the difference in thigh action and upper body rotation between the two men.

It is interesting that after the race Kipchoge said he kept trying to get his legs to spring but they wouldn’t do it. I wonder if something about the living/training conditions in the athlete bubble before the race threw him off.

Legs not feeling springy can of course be a fitness or a fuel issue. But it can also be a movement issue caused by restriction of the pelvis and hip joints: the stance side of the pelvis not moving down and back enough in combination with hip joint hyperextension. Basically the iliopsoas muscle complex doesn’t lengthen enough, though of course other muscles are also involved. I explain this fully here.

Towards the end of the race it seemed to me that Kipchoge’s side-to-side weight shift had taken on a slightly lurching quality, especially to the left–not surprising given the endless right turns of the course. Scrolling through my screenshots of the race, I see a few awkward-looking stances on the left leg. This would be consistent with my theory that restricted pelvis and hip joint range threw him off.

Kipchoge's stance, tilting left

It was, of course, the contrast between Kitata and Kipchumba that defined the end of the men’s race. Kiptata changed his gait–a critical ability for any runner–to access more power and pull ahead to win.

Now wait a minute, you may be saying. Kitata’s got his head way forward! Isn’t that what you just said was a strategy to use less power?

In this case, no. Throughout the race, Kitata’s foward head is achieved through an activation of his flexor muscles to pull him almost into a C shape. The key “tell” is that his head consistently tilts slightly downwards, and frequently dips so that he looks towards the ground instead of straight ahead. You can see it clearly in this screenshot.

Kitata's head frequently tilts downwards as if looking towards the ground

His back doesn’t bend but his swing legs come way out front, and straight. He doesn’t land on straight legs; they correct just before footstrike, but that big forward swing action shows us what muscles he’s using, as does the sense that his shoulders are continually falling a bit behind him.

In the last 400 meters as he duels with Kipchumba you can see his head pumping forward and back as he brings his legs powerfully forward–the size of the leg movement is amazing. His torso is tilted forward but you can’t really call this a forward lean. It’s all work as he recruits his trunk flexors to pull his legs forward.

Clearly it’s work he was totally capable of, and which Kipchumba had no answer for. So exciting to watch.

Speaking of power and thrills, my analysis would not be complete without looking at Sara Hall. She blew past Chepng’etich with the finish line in sight to place second, head tipped back like a modern-day Eric Liddell.

Eric Liddell

So, given all the things we’ve discussed so far about heads, what are the ramifications of Hall’s head position? The answer is simple: air. It’s helping her breathe better. Tipping your head backwards relative to your spine increases the space in your upper airway, letting you get more air in.

(Fun fact: as I was researching this for a recent project, I found that one of the researchers who investigated upper airway space and head position was none other than Sir Roger Bannister.)

The interesting thing about this is that both Kosgei and Chepng’etich were doing the same thing. Their heads were also tipped backwards relative to their spines. This is called atlanto-occipital extension because the occiput, or bottom part of the skull, is tipping backwards in its joint with the atlas (or top) vertebra.

Kosgei’s and Chepng’etich’s heads don’t appear tipped backwards because their spines are tilted forwards. Hall, on the other hand, arches her back to connect her anteriorly-tilted pelvis–another thing she has in common with the other two runners–with her head. The anterior (or forward) tilted pelvis is essential for this kind of performance; I wrote in-depth about it here.

Sarah Hall

Hall’s tilted back head requires a lot of work from the neck muscles in the front to overcome air resistance (or drag). Those muscle contractions interfere with the ability of the neck vertebrae to twist.

You might be thinking, “who cares? The head isn’t supposed to turn when you’re running” but actually the upper body is. And if you’ve got your head facing forward and your neck muscles contracted, you aren’t able to turn your upper body very much, with the knock-on effect that you aren’t able to counterrotate your pelvis very much, and your running becomes more of an arms-and-legs affair.

In the end, her upper body does turn quite a lot as she approaches the finish line, but her head turns along with it rather than facing forward. Runners don’t do this until they’re really tired because the need to see where you’re going predominates over the mechanical benefit of letting it turn, especially when there’s restriction in the neck.

In this, she and Mosinet Geremew in the men’s race have much in common. Geremew leans foward so his head doesn’t appear to tilt back, but his upper body doesn’t turn much and his arms seem to work quite independently of his torso.

With this movement strategy, the arms pretty much have to go front-to-back or do an eggbeater action out to the sides. Hall chooses the former and it fits perfectly with her overall form.

She makes the absolute most of her legs, especially as she catches up to and overtakes Chepng’etich. She knows how to allow her femurs to rotate internally at toe-off so she makes it all the way to her big toes. So few runners, even at this level, know how to do that. It’s essential for good hip extension and getting the full benefit of the arch of the foot. It would be less visible if her pelvis were turning more but it would need to be there nonetheless.

One final thought on tilting the head and breathing. Drag is a real issue for distance runners, even if quantitatively the effect is smaller than for other sports. Decreasing the surface area of the front of the body by leaning forward is the key movement strategy to minimize this, and we see it across many sports.

There has been little research taking into account the role this plays in distance running form, since so much running form research has used treadmills rather than overground running, where air resistance isn’t a factor. Making up for the lack of air resistance by putting the treadmill on an incline doesn’t stimulate a runner to do what they will do in response to that sensation of pushing against air resistance. The best analysis is still Air Resistance in Sport (Pugh 1976), looking at drag across a range of activities all the way down to walking.

More drag means more work a runner has to do. More work generally translates to greater oxygen demand and and runner feeling like they must do everything possible to get enough air. And this deposits a runner into one of several possible feedback loops. In this race we see two of them.

In the first feedback loop, they lean forward, simultaneously reducing drag and opening their airway. This becomes stable.

In the second, they throw their head back, increasing drag and oxygen demand in order to open their airway. As a result, not only is drag increased, but the work done by the entire front of the body, including chest muscles and abdominals, prevents the diaphragm from moving easily downward to take full breaths that effectively get oxygen into the bloodstream. So the difficulty of getting enough air grows rather than remaining stable.

And meanwhile the muscle tension in the trunk and neck block the counterrotation which would balance flexor and extensor tone and generate a foward lean. So leaning forward becomes more and more impossible.

Once you’ve gone into feedback loop two, your chances of changing how you’re running are probably very low unless you come to a complete stop and then re-start.

A third option, which was readily visible among the runners in the pace groups aiming for the Olympic qualifying standard on both the men’s and women’s sides, is to have no feedback loop at all.

In this case, running feels hard, you double down on all your form cues–stay upright, don’t let you chin stick out, contract your abs, lift your knees, etc.–and, lungs burning, you simply slow down no matter how hard you try to run faster.

It’s unquestionably the worst option. Excellent running form, no matter what level of runner you are, means sensing and responding to your environment. It does not mean robotically executing correct movements.

The goal of running form work should be improving a runner’s sensitivity, range of options, and ability to instinctively choose the best. This is why it needs to be approached as education, not drilling. Why it needs to be exploratory, not corrective. And why it’s an ongoing practice, not a task that gets completed.

Hall’s form is responsive. She feels for what she needs to do to find speed and air, and she succeeds. In this, you can see her wealth of experience.

I’d love to see her discover the joys of feedback loop number one, but congratulations are in order for her magnificent performance.

If you’d like to feel the relationship between lean, core action (or trunk counterrotation), and an open airway, you’ll get a simple introduction in my free Mind Your Running Challenge. Sign up here:

If you’re feeling perplexed, enraged, or just want to know more about where I’m coming from, how I do these analyses, and why they’re so different from what you encounter elsewhere, please read this.

8 thoughts on “London Marathon 2020: Kosgei, Hall, Chepng’etich, Kitata, Kipchumba, Kipchoge”

    • Thanks Mark! I also love experimenting with this stuff after I write about it. Had some very interesting runs the past week.

  1. I’d be curious to hear your take on the women’s field over the duration of the race. All the top women had positive splits, including Sarah Hall. What role of form do you think played into how well (or poorly) each of the top women fared in the second half?

    • That’s a big ask, Steven! 🙂 I don’t know that there are direct correlations that can be made with each person’s form and their splits over the duration of the race. The question would be easier to answer if there were some defining feature of the race, like a lot of hills or a high wind, and performance would be affected by how well each runner coped with hills or drag. But that wasn’t really the case here, other than being generally chilly and wet. As I said towards the end of my analysis, there were a lot of runners in the second pace groups on both the men’s and women’s sides who were running upright with really unresponsive form, and a runner who takes that approach has to be having an extraordinarily good day in terms of fitness/fuel/psychology to perform well.

    • They’re closely connected, Alex. The fastest way to run is to use your body correctly. Using your body any other way creates stress and takes extra energy, and this hurts performance. So basic principles of running form that keep runners healthy and injury-resilient, make running feel really enjoyable, and lead to satisfying recreational performance are the exact same principles that give world-class runners an advantage.

      If you look at the lead runners in both the men’s and women’s races, then look at the slower pace groups who are trying to reach the Olympic standard you’ll see a huge difference in form. You see that same contrast in any sufficiently large and competitive race–leaders running with good form and a second tier of finishers with shockingly dysfunctional form who are incredibly fit, driven, and are otherwise doing everything else right. And behind them, at the front of the “masses” you see good form again.

      There are certainly examples of individuals who have run fast with dysfunctional form–Paula Radcliffe and Sammy Wanjiru come to mind–but they’re the exceptions to the rule. Most of the runners at world class level who are in the lead packs of races have good form, and that’s quite consistent with the good form of recreational runners.

  2. There is so much confusion and contradiction in this analysis.

    You claim there’s similarity between Kipchumba and Kosgei, but go on to point out their distinction: the latter’s hip and torso rotation reduces energy requirement while the latter’s upright posture increases it. You claim there’s similarity between Hall and Geremew but go on to point out their distinction: while the former rotates her head when tilting it back the latter keeps it still and compensates with his arms. You claim that Kosgei’s upright posture demands more energy because it requires more extensor activation but then claim Kitata’s posture is equally demanding because it requires more flexor activation. You claim that Hall’s tipping her head backwards helped her breathe better but then claim that the airways actually open when a runner leans forward to reduce drag and that increasing work done by the chest and abdominals when one throws her head back actually prevents the diaphragm from expanding.

    These apparent contradictions are especially problematic as the key claims you’re making here are quite controversial and not supported by evidence. As far as I know, there’s no clear evidence that a gait that recruits either hip flexors or extensor more necessarily requires more energy to do the same work. Similarly, there’s no clear evidence attributing energy savings to a gait with the “just right” amount of torso and hip rotation you’re describing.


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