One month before the year’s biggest track and field event, a dizzying number of fleet-footed performances have lit up local and professional meets.
In the spring, the University of Washington track team produced eight sub-four-minute milers. In June alone, four high school runners broke that barrier in the same race. On the professional circuit, three world records were shattered within a week in Paris in June: Faith Kipyegon of Kenya set a new record in both the women’s 1,500 meters and 5,000 meters, and Lamecha Girma of Ethiopia set a new mark in the men’s 3,000-meter steeplechase.
On Friday night, Kipyegon set yet another record, smashing the women’s one-mile world record by almost five seconds when she broke the tape in 4 minutes 7.64 seconds. The performance stunned track fans accustomed to records that often improve by mere tenths of a second.
The question — why so many fast times? — has been asked and answered endlessly. Wavelight, the pace-setting technology, surely helps. So do the ever-evolving breeds of super shoes — those thick, springy kicks with a midsole plate that have revolutionized racing in recent years by giving higher rebound energy when a runner pushes off.
But many sports scientists see something else: The payoff from several years of training in those specialized shoes. And it’s one that recreational runners can benefit from, too.
“Because the shoes are a new tool, the more we run in them, the better we adapt,” said Geoff Burns, a physiologist and biomechanics expert with the U.S. Olympic and Paralympic Committee.
Burns and other sports scientists have an abiding faith in what is known as the specificity principle: for a runner to compete at his or her best, they have to train in the same way they will race. That means running at their race pace, drinking the same fluids, consuming the same gels, and, perhaps most important, wearing the same shoes.
Super shoes burst onto the scene in 2016 when Nike shocked the world with its first thick-soled, energy-returning shoes, the Nike Zoom Vaporfly 4%. They were so obviously faster than earlier shoes that World Athletics, the governing body of track and field, began limiting the height of a shoe’s midsole in 2020. Now all major shoe companies have super shoes in their lineup, and hundreds of thousands of everyday runners are wearing them.
For elite athletes, it’s become hard to resist the pull of both training and racing in super shoes. Lindsay Flanagan, who has a personal best marathon time of 2:24:43 seconds, will be one of three U.S. women running the World Championships marathon in Budapest in August.
“Since I’m going to be wearing super shoes in races, I want to get a good feel for them in training,” Flanagan said. “I’ve found that I can log more quality days, as well as more mileage in general, because my legs come around sooner.”
But Flanagan also knows some professional runners who don’t train in super shoes. They believe they can build up their strength while wearing traditional shoes, and then gain an extra boost on race day by slipping on the souped-up shoes.
Of course, the “Nietzche principle” can sometimes apply: That which doesn’t kill you makes you stronger. A recent pilot study from California State University, East Bay, found some evidence for this by comparing runner fitness gains in traditional racing flats compared to super shoes. Those who wore the flats complained of more muscle pain, but they also improved their running economy more than runners who wore super shoes.
Two experts in the study of running injuries, Adam Tenforde and Amol Saxena, believe that super-shoe use can lead to serious ailments. In February, they co-authored an article in the journal Sports Medicine that presented five case studies of navicular bone injuries that stemmed from super-shoe use.
“I’ve seen super-shoe injuries in runners at all levels — high school runners, recreational runners and elite athletes,” Saxena said. “The shoes can put atypical stresses on the bones and soft-tissue structures.”
On the other hand, there are no known reviews of super-shoe injury rates that follow standard statistical models. And two leading super-shoe researchers, Wouter Hoogkamer and Max Paquette, say they have seen no convincing data that runner biomechanics are dramatically different in super shoes than in traditional ones.
Both Burns, the physiologist, and Dustin Joubert, an exercise physiologist at Stephen F. Austin State University, have also found that contrary to the assumptions of many, super shoes have a longer functional life than traditional ones. The dense foam midsoles in super shoes, they found, retain their cushioning and energy-return properties longer than the softer EVA midsoles in earlier shoes.
The soft cushioning of super shoes could prove a boon to older runners, too. Bill Salazar, a 77-year-old runner from Arizona, has been training in them for more than three years, logging about 35 miles a week.
“The big benefit for me is that I recover faster in super shoes,” said Salazar, who ran a 4:22 marathon in Berlin last September.
The same cushioning and recovery benefits have been reported by many top runners. They note that they used to “hit the wall” after 20 miles in the marathon, but now, while wearing super shoes, they can finish stronger and faster because their leg muscles are not so fatigued.
In the London Marathon in April, the Kenyan newcomer Kelvin Kiptum wore super shoes while recording the second-fastest marathon time ever, 2:01:25. Kiptum ran the first 13.1 miles in 1:01:40, and the second leg in 59:45.
Apparently, his legs weren’t very tired.
