Better running through physics

By Daniel Holz | December 17, 2010 12:48 pm

I opened the New Yorker a couple of weeks ago to find a feature piece written by Jennifer Kahn, a friend of mine from college. The New Yorker has good taste. Jenn was a fellow physics undergraduate major, but at graduation decided to pursue a career in science journalism. This seems much more challenging than physics; there is no clear career path, supporting oneself financially is a constant struggle, and success is often ill-defined and elusive. But Jenn has succeeded. She is a contributing editor at Wired and a teaching fellow at the Berkeley Graduate School of Journalism. She has published in a wide range of magazines, and has had four articles selected for the annual “Best American Science Writing” series. This is her second feature article for the New Yorker (her previous was on the 9/11 syndrome).

Her article is on Dathan Ritzenhein, a marathoner trying to recapture his glory days. He is being coached by Alberto Salazar, “regarded by many as the best American marathoner ever.” The trick is that Salazar is trying to reinvent the way Ritzenhein runs. And, most interestingly, the approach is to apply science and technology, rather than simply blunt training and fitness, to perfect the athlete. Jenn tells us:

The fastest finishers had a higher thigh drive, for one thing; at its apex, their femur bone was almost parallel to the ground, like the front legs of a bounding deer. They also slapped the ground so quickly with their forefoot that the contact seemed almost incidental. According to Walker, the short slap transfers force more efficiently, shooting it from the ground forward into the pelvis, rather than allowing it to dissipate in the flex of the foot. The effect, Walker says, is like “a pogo stick with a stiff spring.” He explained, “You want the chain of force to travel from the ground through the body with minimal energy loss. That’s what it means to run efficiently.”

I’m not sure any equations are involved, but the basic idea of applying science directly to biomechanics makes sense. The novelty is that it’s not just making a slipperier swim suit or a faster sneaker, but rather it’s an attempt to engineer a whole new way for the body to move.

The story came out the week of the New York Marathon. We now have the benefit of hindsight. Ritzenhein placed eighth, over four minutes behind the top finishers (but still at an unbelievable 2:12:33; I couldn’t keep up for even half a mile, much less all 26+). I guess physics can only do so much.

CATEGORIZED UNDER: Personal, Science and Society
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  • spyder

    Biomechanics has made significant contributions to human movement in the recent years, in many respects due to the need for better prosthetics. Those sleek swimsuits are banned so swimmers are changing their strokes to increase efficiencies and challenge suit-aided records. Runners are changing strides, foot falls, and even running barefoot. Lots of research is happening at this point in time, which is really cool, given that we are alive to experience it.

  • psmith

    Yes, the New Yorker has good taste, that was an enjoyable article. But changing a runner’s form seems to be an exercise in futility. That at least was my experience.
    Some runners are gifted with the ideal biomechanics, biochemistry as well as psychological make up and there doesn’t seem to be much that high tech training programmes can do to overcome such advantages. But we learn so much from trying to do what seems impossible.
    Researchers at the University of Utah have argued that endurance running is the one activity that has uniquely shaped the human animal. That for much of our early history we depended on efficient endurance running as we were essentially persistence hunters. Perhaps the Kenyans and Ethiopians have retained these advantages better than we have.

  • ian

    If we evolved for endurance running, why do we suck at it so much? I know, we’re better than most animals, but we are unable to even do it without a lot of practice. Dogs and horses bred for distance running are way way better than us. I’d be more willing to bet we evolved to be able to walk forever (say, 12 hours straight) while carrying or manipulating stuff with our hands, since that’s something pretty much any healthy person can do if forced.

  • Tyro

    Ian – I think you’re looking too much at todays world where we use technology to allow us to maintain sedentary lives so that even walking for 2-3 hours is more than many Americans are able to do. The question isn’t what any person in today’s world can do after rolling off the sofa, it’s what people who grow up in a primitive society can do. As a comparison, there are about 70,000 Tarahumara Indians in Mexico yet because they grow up doing endurance running, were able to field many runners who competed with the best runners in all of the US (which has 50 times their population). Just looking at the figures the article quotes, 13 of the top 25 fastest marathon times are Kenyan and 9 are Ethiopian yet combined these two countries have 1/3rd the population of the US alone. If you just look around you and try to extrapolate to what humans can do at birth without the effect of culture and technology, you’re going to reach some bad conclusions.

    I read of studies of groups that hunted using endurance to outrun prey in Africa and they showed that this style of hunting offered a very high success rate and big rewards with relatively low risk and cost and could be used at all times of the year (with variations for prey and local land conditions).

  • ian

    I don’t think Kenya or Ethiopia really count because the great marathoners they produce seem (from my perspective) to be doing it to overcome poverty and escape their country. Are there cultures that actually survive primarily by chasing animals?

    I’ve always been in good shape, am in my mid 20’s, and could probably run a marathon if under sufficient stress without actually dying. But I don’t think that really counts – I still don’t think I’m good at it. Rather, it seems like it’s just something on the edge that is barely possible.

    My point, which I think may not be completely true (but perhaps mostly true), is that the things animals have evolved to be good at they are to a substantial degree simply good at – they may improve by practice, but will still outclass other species. Examples: Tigers or bears that spend their lives in a zoo not exercising will still be vastly stronger than most other creatures, and probably still have a fighting chance of survival by hunting if tossed into the wild. At the very least they will have the instinct to hunt, and attempt to do it. Same with dogs and wolves.

    However if you take a person (think corporate office worker) and release them into the wilderness, I just can’t imagine them having the instinct or ability to even attempt to chase down prey until it becomes exhausted. They are going to wander around looking for anything edible, and maybe try to figure out a clever way to catch something small.

    The biomechanics of running article is actually fascinating, and the barefoot running trend is interesting, but I just don’t think the evidence that we evolved to do more than be able, with a struggle, to run long distances is that compelling. We’re pretty decent at traveling longer distances slowly, but running… I just don’t see it.

    Along the same lines, higher mathematics is another thing that we can do, but didn’t evolve to be great at. We are ok – it seems we can figure things out – but beyond the initial abstractions (natural numbers, basic geometric reasoning…) it’s a skill that takes real effort and is not widely distributed across the population.

  • psmith

    Ian, yes there are cultures that survive primarily by chasing animals. The San Bushmen of Southern Africa do this. Tyro actually referred to one of the published studies documenting this. Have a look at the University of Utah studies, they are persausive. Just to illustrate with a personal anecdote. I do trail running with my two dogs in a hot, arid environment. Up to the two and a half hour mark they can out run me. Thereafter they match my pace. After the three hour mark they slow noticeably and at about three and a half hours heat exhaustion brings them to a standstill while I can continue for much longer until dehydration stops me. My dogs’ cooling ability is limited by the length of their tongues, which in turn is limited by the size of their mouths. By contrast, since we depend on whole body sweating and not our tongue for cooling, we have a much larger surface area for cooling so we can dump more heat and therefore run for longer.

  • Tyro

    Ian – again, it’s a ridiculous standard to look at indolent office workers and conclude that humans aren’t built for running. You say that Ethiopia is a bad standard because they’re running to escape poverty – that sounds like a very good comparison with the pressures our ancestors faced to gather food.

    As for running marathons, I think you’d be shocked at how far you can push yourself. I worked myself up from running 10km to 40km in four months and it took another four months to get up to 80km. I’m pretty confident that if I wanted to, I could double that again to 160km (100 miles) as many people have done before me. Try to find another pursuit where you can double your maximum three times in eight months. Getting to be a fast runner takes some hard work as the article comments on, but gaining endurance is surprisingly easy. When you find a good pace, almost any person can run for hours and be relatively comfortable, especially if they work up to it for a few months and carry a supply of water and food.

  • Robert

    I’m guessing humans became better distance runners because we could keep a specific goal in mind longer, and imagine positive outcomes of an action further in the future than other animals. Since we were willing to work longer at achieving a goal, we became better at doing that work for longer periods of time.

    Any takers? : )

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