Is this the shoe that will help rewrite marathon history?

Will a new generation of high-tech footwear finally make it possible for elite runners to complete a marathon — 26.2 miles — in less than two hours?

Since the 1970s, Adidas, Nike, and other shoe manufacturers have battled one another to create a shoe that will enable someone, somewhere to complete the first sub-two-hour marathon. And treadmill tests conducted recently at the University of Colorado suggest that a shoe Nike introduced to the public last summer could be just the ticket.

In the tests, runners wearing a prototype version of the company’s $250 Zoom Vaporfly got a boost in running efficiency roughly 4 percent greater than that provided by Adidas’s Adios Boost 2, the previous “gold standard” shoe favored by many elite marathoners.

“This new shoe is the most efficient shoe in terms of the energy required to run that anybody has ever studied,” Dr. Rodger Kram, associate professor of integrative physiology at the university and leader of the research, says in a video released by the university. “Theoretically, if it can enhance performance this much, it should get a runner well under two hours.”

In Monza, Italy last June, the current Olympic marathon champion, Eliud Kipchoge, ran a marathon in 2:00:25 in a special event aimed at breaking the two-hour mark. Wearing Vaporflys, which feature lightweight cushioning and carbon-fiber plates in their soles, Kipchoge ran almost three minutes faster than his previous best.

But that remarkable time may have been less about the shoes than the race conditions.

Dr. Michael Joyner, a Mayo Clinic researcher who predicted that a sub-two hour marathon might be physiologically possible back in 1991, notes that Kipchoge had help from a team of 30 pacemakers, who helped break the wind. What’s more, the course had no sharp turns, and Kipchoge didn’t have to slow to grab drinks because they were handed to him by a cyclist.

“He might have got a marginal gain from cheap new balance shoes 574  the shoes, but is somebody going to buy them and suddenly magically run 4 percent faster in a real race?” Joyner asks. “Unlikely.”