When Nike announced last month that three of its athletes would seek to run a sub-two-hour marathon this spring, the image that leapt to mind for many people—me included—was of a giant science experiment. But not all science takes place in the lab.

This week, the Breaking2 team is in Kaptagat, Kenya, where Olympic champion Eliud Kipchoge is training for the sub-two attempt. Next week, they’ll head to Ethiopia to work with two-time Boston champion Lelisa Desisa; then they’ll continue to Madrid, where half marathon world record-holder Zersenay Tadese is currently training.

The goal of the trip is, in part, scientific. Each athlete has been training with a GPS watch and a heart-rate monitor, and uploading their data nightly for analysis by the Nike’s NXT Generation Research team. The researchers will meet with the athletes and their coaches to share their insights. Apparel, shoe, and biomechanics experts are also on the trip, with enough prototypes to fill a matatu.

So what will they be telling the athletes? Well, that depends. When I chatted with two of the senior Breaking2 team leaders last week, one thing that became clear is that there’s no single “Breaking2 Plan.”

From their analysis of the athletes’ training so far, they’ve found that each of these three very accomplished runners approaches their training in a very different manner, both on a day-to-day level and also in how they organize the ebb and flow of training over weeks and months. So Nike won’t be trying to shoehorn each athlete into one master plan; instead, they’ll be offering whatever insights and feedback they can to support what the athletes are already doing.

Of course, not everything can be individualized. I asked whether the team had settled on a pacing strategy for the record attempt; the answer was no. Moreover, each of the three athletes has different ideas about the best way to approach the race. This is a serious question, because Nike’s modeling suggests that getting the early pace wrong by as little as 0.05 kilometers per hour (which works out to a difference of less than a second per mile) can slow you down by tens of seconds later in the race.

So everyone needs to be on the same page by race day—and everyone needs to be confident that the group decision is the right one. Scratch beneath the surface, and you find that this dilemma, and others like it, is the real reason Nike is leaving the lab and flying to Africa. It’s not enough to use a supercomputer to calculate the optimal pacing strategy; you also have to have earned sufficient trust from the athletes that they share your belief in that pacing strategy.

Temperature presents a similar dilemma. No matter how good your model of human thermoregulation at two-hour pace is, it’s useless if the “optimal” temperature it suggests is so cold that the athletes are uncomfortable and psychologically off their game. That’s one of the reasons why the location and even the time of day of the attempt haven’t yet been finalized: the human factors matter.

For that reason, some of the field testing the athletes will be doing during the trip is as much for their own benefit as for the scientists.

For example, they will wear a body-mounted device to measure wind speed, and practice running in various drafting configurations. It’s one thing for the scientists to say “Based on wind tunnel testing, you must run exactly 42 centimeters behind your pacer, at an angle of 16 degrees to the left.” It’s another to go out for a run and try moving to various positions behind other runners or within a pack, and see for yourself which one minimizes the wind resistance while also being comfortable enough to maintain without fear of tripping.

Another piece of gear Nike is bringing will non-invasively measure levels of glycogen (the form in which carbohydrates are stored in muscle) before and after various workouts.

The athletes have been experimenting with a variety of nutrition products over the last few months. All the options are ordinary over-the-counter products (they’re not using, for example, the experimental Swedish drink that the rival Sub2 project has provided to Kenenisa Bekele); it’s more a question of figuring out which products work best for each individual athlete.

Being able to directly measure the change in fuel stores will help pick the best drink—and just as importantly, help the athletes themselves see the difference that effective fueling makes.

That may sound like pretty basic advice, but it could be crucial. Why does Tadese, the half-marathon record-holder, have a mediocre marathon best of 2:10:41? When I chatted with his coach, Jerónimo Bravo, last month, he put the blame on fueling problems: missed drinks in some of his marathon attempts, but also difficulty finding a drink that works for him.

When Tadese finished his 2:10 marathon, Bravo recalled, the first thing he wanted was a sandwich—a fairly unusual request for someone who has just slogged through 26.2 miles, but indicative of the fact that he had bonked badly and was out of energy. For Bravo, then, the biggest area where he’s looking forward to help from Nike is nutrition.

When the Nike team returns from Africa (and Spain), I hope to have an update on how all this testing went.

For now, the biggest news from my most recent conversation with the team is that they’re setting the necessary wheels in motion to ensure that the course they select will be certified according to IAAF regulations. Given all the speculation about downhill courses that followed the initial announcement, that’s a huge relief. In practice, it means that the start and finish of the course can’t be separated by more than 50 percent of the race distance (i.e., 13.1 miles), and the overall decrease in elevation can’t be more than 1 in 100. For a marathon, that’s 42.2 meters in total, or 138 feet; for context, the California International Marathon, a notoriously fast course, drops 340 feet from start to finish; Boston drops about 480 feet.

That doesn’t mean the overall race will be record-eligible. It won’t be, for reasons that haven’t yet been specified. There are possible disqualifiers ranging from subtle to egregious; the comparison I made in my last update was to Roger Bannister's first four-minute-mile attempt, where the use of lapped pacers rendered the attempt unratifiable.

Still, the fact that the course itself is slated to be record-standard is good news. Whatever other advantages they’ve got, Kipchoge, Desisa, and Tadese are going to have to the cover the distance over more or less level ground. Whether they can do it remains to be seen, but the picture will start to look a lot clearer after this week’s training camp.

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