Three groups, one from Nike, one from Adidas, and one independent project, are currently pursuing the seemingly far-fetched goal of Health - Injuries. Ways to Make Running This Winter More Enjoyable? Other Hearst Subscriptions Health - Injuries Sports Medicine argues that some relatively simple adjustments like lighter shoes and a cooperative drafting strategy “could result in a time well below the 2-hour marathon barrier.”

The analysis comes from Wouter Hoogkamer and Rodger Kram of the University of Colorado, and their former colleague Christopher Arellano, who is now at the University of Houston. Using Dennis Kimetto’s world record of 2:02:57 as a baseline, they consider a wide variety of approaches that might enable a runner to cover 26.2-miles the required 2.5 percent faster.

Some of them are pretty obscure. For example, since about 80 percent of the energy cost of running goes to supporting your bodyweight and propelling yourself forward, they consider ways of reducing the runner’s effective weight. They decide to leave aside the possibility of running the race in the weaker gravity of Mars or the Moon (though they cite a paper on the relative merits of skipping versus running in low gravity)—but what about heading to the equator, where gravity is about 0.31 percent less than in Berlin, where Kimetto’s record was set? That could offer a time benefit of about 15 seconds, they calculate—but such a benefit would be counteracted by the typically warm weather near the equator.

Such pros and cons dog many of the ideas they consider, but a few stand out as promising options. One is shoe weight: reducing the mass of your shoe by 100 grams (about 3.5 ounces) shaves about one percent from race time, according to a recent study by Hoogkamer, Kram, and their colleagues.

Another is drafting. IAAF rules prevent the use of pacers who join the race partway, so most world record attempts involve running alone, or at least without a pacer blocking the wind, for the last 10K or more of the race.

The new paper, instead, explores the effects of cooperative drafting, as used in cycling breakaways and team time trials. Even if you don't stay sheltered all the time, you get a net benefit from alternating leads with another runner.

The paper considers the benefits of having four runners taking three-minute turns in the front of a single-file line, running one meter apart. For runners capable of running a solo 2:02:57 marathon, running in this manner just for the second half of the race would allow them to run that half in 58:51 with no additional effort. With just two runners alternating leads, the second half would still be run in 59:30. In comparison, if you allowed fresh pacemakers to jump in at the halfway mark, the same effort would theoretically produce a 57:22 second half.

In addition, if you could design the ideal course, you might arrange for the second half to be downhill to the maximum extent permitted by the IAAF, which is 42.2 meters over the course of a marathon. Such a scenario would save another 28 seconds, the researchers calculate. And if you could arrange a modest tailwind for that segment, that would be even better.

Finally, in addition to the weight of the shoes, there are other aspects of shoe design that could help shave time. The springiness of the midsole cushioning, such as the Adidas Boost foam in the shoes Kimetto wore in his record run, appears to help. The researchers also cite a 2006 study in which the insertion of a carbon-fiber plate to stiffen the midsole of a running shoe reduced the energy required to run—an approach echoed in a recently published Nike patent.

Putting it all together, the researchers present two scenarios. In both, a hypothetical Kimetto-like runner wears shoes that are 100 grams lighter than his record-setting shoes, allowing him to save 32 seconds and hit the halfway point in 1:00:57.

Then for the second half, the course shifts from a flat, sheltered loop to a mild downhill that descends 42 meters (saving another 28 seconds), while the runner either drafts cooperatively with three peers (let’s call them “Bekele,” “Kipchoge,” and “Kipsang”), finishing in 1:58:21, or is pushed by a 6 meter-per-second (13 mile-per-hour) tailwind, finishing in 1:58:27. It’s an either/or, because you can’t fully benefit from cooperative drafting and a tailwind at the same time.

So that’s how it could, according to these calculations, be done. Is that how it will play out in the real world? While Kram is a consultant to Nike, the paper notes that “the views expressed in this manuscript do not represent those of Nike, Inc.”

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