Abs were the focus of my analysis of the finish of the men’s race in Boston, and it turns out they’re also a key point of interest in the women’s race in the 2019 London marathon.
I’ve written about Brigid Kosgei, the women’s winner, a couple of times before. In Chicago 2018 I said she had a “perfect runner’s contrapposto,” though in London 2018—in the high speed footage I captured of her from the side—her movement seemed somewhat exaggerated to me. In London this year I finally understand what’s going on, thanks to the extensive opportunities to watch her from the front and contrast it to second-place Vivian Cheruiyot’s.
Have a look:
You may notice Kosgei’s large frontal-plane (side-to-side tipping) pelvis movement. You’ll also see that her feet hit the ground almost in a line, as if she were running on a tightrope.
These two things are tied together by what’s going on in her abdomen: contraction. Whether intentionally or otherwise, she appears to be pulling her belly in. As confirmation of this, it also appears her chest is slightly lifted and expanded—just like what happens when you suck your belly in and try to button the jeans that fit in high school. (Or maybe that’s just me. 😉 )
She’s not doing it as much as that, and certainly not as much as Sara Dossena did in NYC last year, and she also doesn’t appear to be doing what Dossena did in trying to pull her pelvis upright. She’s still allowing the anterior tilt that’s essential for a forward lean and long stride length, she’s just got the muscles active and pulling in slightly.
As additional confirmation, you can see in the few steps she takes right after crossing the finish line that her abdomen is still pulled in and lower ribs slightly but distinctly lifted. Later in the video, as she’s being herded around for photos and interacting with other runners, you can see a change in her belly, a slight roundness and that tiny donut of fat around the navel that healthy women have—even very lean ones. (We could go down a deep rabbit hole on this issue, but I’m going to just leave it at that.) That change confirms again, she was pulling her belly slightly in.
I know that doing this is popular advice for runners, supposedly it protects your back and makes your form better, etc. There are actually a number of different ways it could play out, but none of them are particularly good.
For Kosgei, the synergistic relationship between the abs and the inner thigh muscles causes her tightrope-style gait, just as it did for Joe Pilates. This means it’s tough for her to use her glutes. It also makes it hard for her hip joint to pass her stance foot and allow her leg to extend behind her (that’s hip joint hyperextension for those who favor correct anatomical terminology).
To feel how that works, lie on your side with your knees bent in front of you like you’re sitting in a chair. Lift your top leg up a little and, keeping the knee bent, slowly start to move it in an arc so the foot and then perhaps the knee passes behind you. Keep the knee and foot the same height from the floor the whole time, so you’re moving your leg on a plane parallel to the floor. Feel how far back it goes if you don’t stretch or push it.
Then bring your leg back in front of you and put it down on top of the bottom leg. Repeat the action of moving the leg on an arc backwards you, but this time don’t lift it up first. Just take it straight backwards from its resting place on top of your lower leg. In this version you’ve got it much closer to your midline as you try to take it backwards. How far does it go without stretching or pushing?
Continue to experiment with having the leg at different heights from the floor and see at what height it is easiest to move behind you and goes the farthest.
You’ll find that the backwards movement is quite limited if you don’t lift the leg first. If your knee and foot are closer to your midline than your hip joint, it’s tough to get the leg back. The leg needs to be in line with the hip joint for you to have a good range of motion and a low level of effort in moving the leg back.
So this is what happens with a narrow gait. The upper leg is too close to the midline to move behind the hip joint easily after the pelvis passes the stance foot. A lot of runners who do this simply don’t extend their hips that much. Here’s more about hip extension and what you can do to improve it.
Kosgei, however, has a workaround—literally. She tips her pelvis more than the usual amount sideways to bring her hip joint into better alignment with her knee. Hence the fairly large sideways tipping of her pelvis, and the almost whiplike counterbalancing oscillation of her upper body and arms. This allows her thigh to pass behind her (or, more accurately, her pelvis to pass her thigh) for a good stride length.
Cheruiyot does all of this differently. Her gait is much wider, each foot falling in line with the hip joint. Consequently she doesn’t have the exaggerated tipping action of the pelvis. It’s there, in just the right amount to shift her weight from leg to leg and function as part of the spring system, storing energy in the torso during the compression of midstance and returning it in late stance to propel her forward. We know it’s working well because she looks so smooth.
From the side you can see that her abdomen isn’t pulled in the way Kosgei’s was, and not coincidentally her glutes are bigger and stronger. The moment she stops running, you can see her abdomen is relaxed. And as the third, fourth, and fifth-place runners come in after her, as different as they all are from each other you can see that their abs are also relaxed.
Am I saying runners shouldn’t use their abs, or these runners aren’t? No. But the action of the core muscles is fundamentally rhythmic in coordination with footstrike, not ongoing, and the stabilizing action of the transverse abdominals (the ones that pull the belly in) and pelvic floor are regulated subconsciously, as needed. Continually pulling your belly in when you run interferes with your breathing and the proper use of your glutes, and wastes energy.
“But Kosgei won!” you might be thinking. Yes she did. Perfect form doesn’t win the race, it’s just one of many strengths a runner may have. And Kosgei does, as I pointed out, have a workaround that clearly works for her and also is unlikely to cause any kind of injury.
In my analysis of the Boston marathon last week I wrote about how the top three men used different arm strategies in their final kick down Boyleston St. In London, Kipchoge running through the later miles with Mosinet Geremew and Mule Wasihun on his heels was a parallel scenario, but with a key difference.
In Boston it wasn’t clear who was going to win. In London it was.
Geremew and Wasihun pumped their arms significantly harder than Kipchoge as they worked to stay with him. Their effort at that speed was clearly higher than his. And sure enough, when Kipchoge decided to drop them he simply pulled away.
That difference in effort was to some extent a chicken-and-egg thing. Kipchoge was faster, therefore he wasn’t working as hard. But there was a difference in the nature of their armswings as well. Geremew and Wasihun had more arm movement independent of their upper body rotation than Kipchoge did at that speed. And when Kipchoge sped up, his arm movement did increase in size but his upper body movement increased along with it.
This highlights video starts just after that point:
(Unfortunately this highlights video is a little deceptive, because it starts just after Kipchoge moved into kick mode, opening his hands a bit and directing them forward in space, in a nod to sprinting technique. It doesn’t help him, and believe me, he didn’t run the rest of the race this way. It’s only his hands that he does this with—his arm action is unchanged, so you can still see what I’m describing.)
I talk a lot about armswing because it’s so strongly indicative of the forces traveling through the body, how the runner is controlling the torque from the lower body, how they are balanced in gravity, how they’re handling ground reaction force and converting it into movement, and whether there’s any extraneous effort in their form, sapping their energy and hurting their performance.
In this race I kept looking at Kipchoge’s long, almost vertical hand movements down the front of his torso, right along where the zipper of a jacket would lie. This was pronounced at the beginning of the race and again at the end, after he dropped the other two.
A movement like this isn’t made just by the arm, it’s also the trunk muscles on the same side of the body and the gluteus medius on the opposite side working together to tilt the pelvis, bringing the swing leg through and lengthening the stance side of the body. Kipchoge does it very powerfully. I’m not sure I’ve ever seen anyone else do exactly that with their arms.
In other words, in this way and in many others, Kipchoge’s armswing could be said to drive force through his body to his legs.
Geremew and Wasihun, each in their own way, used their arms more to counterbalance and thus drive their legs, but less to act on their legs via the torso.
And what were their own ways? In Geremew’s case it was to pull his upper chest back or, looking at it differently, to round his upper back. That action actually keeps the arms from integrating with the ribcage and spine as well, since there’s chronic muscle tension in his chest and back around this bit of flexion. You can see shortly after he crosses the finish line his chest sags backwards and he walks stiffly on his heels.
Wasihun’s upper body clearly shifts side-to-side and turns slightly but not as much as I’d expect. He’s broad-shouldered, something I always feel is an advantage, and so it may be that he needs to turn less to produce the same leg action.
But as he downshifts to a jog after crossing the finish line he stops swinging his arms and lets them ride his upper body movement, and suddenly his shoulders turn much more. So there’s potential there for him to spend less energy running at higher speeds, as movement closer to the center of the body costs less energetically than movement farther out, and he clearly can do it.
I was also very interested in how he reduced the length difference between his legs by running on the outside of his left foot. I’s a resourceful solution though I imagine it also requires some extra body care and maintenance.
Having Eliud Kipchoge and Vivian Cheruiyot in the same race always creates a pleasing symmetry, since their form is in many ways so similar. It’s easier to see what’s happening with Cheruiyot’s torso than Kipchoge’s because of the difference in clothing, but if you look at the beginning of the men’s video again, from the point that Kipchoge is filmed nearly from behind through the finish line you can see the churning in his hips and midsection in the way his shirt drapes and shifts.
These two runners both have amazing forward leans and powerful engines between shoulders and hips that make their running truly beautiful and powerfully functional. Go out for a little run after you finish this and try it on for size.
Sign up for our free weekly newsletter filled with analysis, information, insights, and tips you can apply to your own running!
Jae Gruenke, GCFP, is a running technique expert and Feldenkrais Practitioner. Known as a “running form guru,” she is the Founder and CEO of The Balanced Runner™ in New York City and The Balanced Runner UK. She has helped runners from beginner to Olympian improve their form to become pain-free, economical, and fast.