The technology for racing shoes has come a long way since Abebe Bikila won the 1960 Rome Summer Olympics barefoot. Today’s cracks at the marathon world record are part athletic prowess, part high-tech, rebound-inducing racing flats. Nike’s Vaporfly 4% claims to make runners four percent more efficient with a blend of foam and carbon fiber. But, whether the terrestrial runner needs all that tech, and whether it could harm more than help, is another matter entirely. We borrowed the expertise of Severin Romanov, of running technique coaching firm Pose Method, to help you find the flats that shave seconds off your next race.
Another way to shave seconds off your next race is with Aaptiv. Check out our running and cross-training classes in-app.
Why the Appropriate Amount of Cushioning Matters
A racing flat is essentially a stripped-down version of a traditional trainer. It is designed to have enough cushioning and support for long-distance racing, but a minimal amount of mass. In 1965, University of Oregon coach Bill Bowerman designed his own racing flat. This was after dissecting his athletes’ shoes and realizing a lack of cushioning was causing stress fractures. The most popular shoe of the late ‘60s and early ‘70s was the resulting Nike Cortez.
“Some variability in cushioning is a good thing. And helps us select the appropriate type of shoe for the surface we are running on,” Romanov says. “Mid-level cushioning for urban/concrete areas, and low cushioning for grass and trail [are best], since the surface is already plenty forgiving.” Thus, running in an urban environment doesn’t lend itself to logging serious mileage in racing flats.
Be wary of too much cushioning.
Too much cushion can be unproductive. “Maximalist shoes are almost always a deterrent for us. We liken them to jumping on a trampoline or bed springs for 15 minutes,” Romanov says. Think about the moment that you get off a trampoline. Your legs are stiff as if the ground got harder. “If the shoe has too much cushioning, after full body weight loading, the foot continues to be unstable and collapse when on support,” he says. “Thereby, asking the rest of your body and joints to increase their own stiffness to compensate for this lack of stability beneath you.”
The key is to consider the total stress you’re putting on your legs. This includes the surface on which you run and your total running volume, Romanov says. “If the outside surface is soft, you can opt for a more minimal shoe,” he says. “If you’re running on pavement, you’ll probably want more cushioning and sturdiness to go with it to withstand those types of runs.”
Substitute cushion for lightness on fast runs and races.
The reason why you’d substitute some cushioning for lightness, thus inherently increasing injury risk on hard surfaces, is simple. It makes you faster. The definitive study on racing flats happened in 1982. Led by biomechanics researcher Edward Frederick and famed coach Jack Daniels, the research team discovered that adding 100 grams of mass to a shoe increases a runner’s submaximal oxygen uptake by one percent. Or, in Daniels’ math, an ounce of weight reduction shaves 0.83 seconds off a 5:40 mile. According to that calculation, switching from ten-ounce trainers to six-ounce flats over the course of a similarly paced 10K would save 20 seconds.
There is a performance limit to weight reduction, though. A Medicine and Science in Sports and Exercise study found that running barefoot is three to four percent more metabolically demanding than running in racing flats. Using flats in that sweet spot of weight savings and adequate support while training at race pace can acquaint you with a speedier, race-day version of yourself. Severin’s father, Dr. Nicholas Romanov, occasionally has runners do a 10K training run, then ten by 200-meter sprints to focus on speed. Switching to racing flats for the speed work not only means faster practice times but also becoming comfortable with the shoes you’ll be racing in.
Aaptiv has running classes that specifically focus on speed work, so you can tackle your next race with technique and confidence.
How to Find the Right Secondary Shoe
If you already have a dependable, adequately cushioned set of trainers, your secondary shoe could be a racing flat. Or, it could be a slightly lighter trainer, depending on what you’re ready for. In a discussion of running shoe research, eminent biomechanist Benno Nigg concluded that comfort, above all else, is the best determinant of a shoe’s utility. “How the shoe fits your particular foot made more of a difference than any marketed technological advancement,” Romanov says, in reference to Nigg’s review. With comfort in mind, here are a few of Romanov’s tips for finding the perfect racing shoes.
Your form doesn’t break down right away.
The best running posture will still disintegrate once you become exhausted. But if you’re struggling to hold it together in the first couple miles, that’s not a good sign. “Some good, common sense indicators of good technique are a light, quick cadence, and not hearing thuds on each landing,” Romanov says. Be cognizant of your form and try the racing flats in training to make sure that they won’t ruin your upcoming race.
There’s an appropriate amount of rebound.
Just because an elite marathoner runs well in five-ounce, half-carbon fiber racing shoes doesn’t mean that you will (no offense). “It’s like buying a race car and thinking that because you have a fast car, you are now a race car driver,” Romanov says. World-class runners have low ground contact times. This allows them to benefit from a high-rebound shoe. But mere mortals have higher ground contact times. “Most runners don’t have a cadence that’s quick enough to utilize the purported benefits of active rebound,” Romanov says. When the foot is on the ground too long, active rebound exerts the extra force back into the lower leg. “You can fill in the blanks with your favorite lower leg injuries here,” he says. Unless you’re well-trained and really fast, be wary of any racing shoes that claim an extra-high energy return.
It’s not too light.
Similar to having too much rebound, racing shoes that are too light can become a detriment before the race is over. “Sometimes a shoe that is too lightweight may not be constructed rigidly enough to support a longer (ground) support time,” Romanov says. A heavier shoe with more support, he adds, might be a net training benefit. It allows you to increase your volume without getting injured or overly sore.
Another way to avoid injury is with proper training technique—and Aaptiv’s trainers are here to help.