Those Superfast Nike Shoes Are Creating a Problem

By Amby Burfoot for the New York Times

The people who oversee track and field have to give serious thought to how much running-shoe technology is too much. Last weekend’s extraordinary marathon performances — 1 hour 59 minutes 40 seconds by Eliud Kipchoge in Vienna and 2:14:04 by Brigid Kosgei in Chicago — have focused attention on an already simmering question: Does the International Association of Athletics Federations need a more stringent rule to define legal running shoes?

It appears that running, the original and most elemental of sports, now faces the same tradition vs. scientific innovation challenge that other sports have encountered. Think: tennis rackets, baseball bats and, perhaps most similar, competition swimwear — those polyurethane-based suits that were banned starting in 2010. The outcome of the current running-shoe debate could affect everything from stock prices of global footwear companies to who wins the Olympic marathon in Japan next summer.

Kipchoge, who became the first person to run the 26.2-mile distance in under two hours, and Kosgei, who set a women’s world record, raced in a revolutionary and bizarrely tall Nike shoe that has taken the marathon world by storm since 2016. In the last 13 months alone, male runners in the Nike shoes have recorded the five fastest marathon times ever. Other running-shoe companies are struggling to catch up, and may face patent hurdles.

The current I.A.A.F. rules state only that shoes may not confer an “unfair advantage” and must be “reasonably available” to all. The rule does not explain how these two values can be measured.

This week, the British Journal of Sports Medicine published a commentary that is likely to guide the debate. In it, Geoffrey Burns, a 2:24 marathoner and University of Michigan doctoral candidate in biomechanics, argued for “a single standard in competition running shoes: regulate the shoe midsole thickness.”

With the right material, a thicker sole produces more spring. Without clear restrictions, it is likely only a matter of time before someone comes up with a way to make a shoe with more powerful springs.

Burns called for an upper limit of 31 millimeters — about 1.2 inches — of midsole. Nike’s current Vaporfly 4% and Vaporfly Next% shoes have a 36-millimeter midsole, or about 1.4 inches. Why 31 millimeters? That’s a fairly common midsole height for previous models.

Until 2016, marathon racing shoes were constructed from thin slabs of rubber. In 1960, an Ethiopian runner named Abebe Bikila even managed to win the Olympic Marathon in his bare feet. Everyone understood that less was more; you ran more efficiently when you carried minimal weight on your feet.

In 1968, when shopping for the shoes that carried me to victory in that year’s Boston Marathon, I had only two criteria. They had to be light and thin, and they had to be cheap. I was still in college. I paid $9.95 for my lucky shoes — a pair of Onitsuka Tiger TG-4 Marathons.