I Tested Super Shoes Just Like Sports Scientists to See What Makes Them Work

THE HARDEST THING about running during a lab test: I become a mouth breather. I’m hooked up to a computer via a tube clenched between my teeth. My nose is plugged with a pair of plastic blue pincers, cutting off the ability to inhale through my nostrils. The whole rig is held in place by a headband, which I need to tighten between each five-minute round on the treadmill. I suck in air, but I mostly feel like I’m only getting about 60 percent of a breath as I run near my marathon pace. Every time I start to feel comfortable, it’s time to step off for a quick break, ostensibly to keep me from getting too tired.

I’m at Puma’s North American Headquarters in Boston, testing out the new Fast-R Nitro Elite 3, a sleek, space-age-styled super shoe that just dropped. But at the moment, I’m more interested in the lab, and the process used to test the top-flight sneakers that have become synonymous with high-level performance for everyone from the sport’s top athletes to your buddy looking to run a fast 5K.

The great super shoe race has remade the running world and rewritten its record books. New designs with carbon plates and responsive foams brought sports performance concepts like “running economy”—which used to be the exclusive territory of product developers and physics nerds—into conversations at neighborhood run clubs.

Everyday runners, however, might not totally understand what these phrases actually mean—let alone how the footwear companies measure the shoes to make assertions about performance. Is there a technical framework behind the hype, or is it all just savvy marketing? That’s what I wanted to find out when I agreed to visit Puma’s lab to put the protocols the brand (and lots of its peers and sports scientists, too) use to put their shoes to the test.

What Is Running Economy, Anyway?

When sports scientists measure “running economy” (the main measure of success for carbon plate super shoes), they’re not talking directly about speed. So when anyone claims carbon plate super shoes will instantly make you “faster”, they’re skipping a few important steps and simplifying what’s actually happening between your body, your feet, and the road.

“The easiest way to think about running economy is to think about your car and its gas mileage,” says Wouter Hoogkamer, an assistant professor of kinesiology at UMass Amherst. Hoogkamer has been involved in some of the most consequential research projects of the super shoe age, most notably the 2018 study that validated Nike’s claims that their first entry into the category could yield a four percent improvement in running economy. “For running, we sort of have the same thing where the amount of energy you use to run at a specific speed depends on how efficient you are as an athlete and how efficient your gear is—in this case, the shoes.”

That’s why I have a tube in my mouth. Breath is key to gauging efficiency, according to Hoogkamer. “In the lab, we measure that [efficiency] mainly by looking at oxygen uptake,” he says. Oxygen, he says, burns the food you eat into the energy that your muscles use to create the forces that propel you forward with every stride. By measuring the oxygen I’m breathing in and out, researchers can understand how effectively I’m using my energy to move and run.

Shoes that help you move more efficiently allow you to use less oxygen and burn less energy. And if you’re conserving energy with every stride, you’ll get through a race with less fatigue, or you’ll have more energy to pour into your strides late in a race. Runners can improve their efficiency in a variety of ways that don’t cost a penny (including strength training or various running workouts). Adding equipment (like super shoes) is one method. Hoogkamer likens it to swapping old tires for new ones in your car: Your engine hasn’t changed, but the fresh treads make your car faster.

According to Colleen Brough, D.P.T., an assistant professor at Columbia University and the founding director of the Columbia RunLab, the components of super shoes—the carbon plate and hyper-responsive foam—let you hone your stride, or gait cycle. The gait cycle begins when the foot first touches the ground (or treadmill). The runner then shifts weight onto that foot and enters the “mid-stance,” when the foot is directly under the body’s center of mass. Next is “terminal stance,” when the heel rises and the foot is behind the runner, pushing off the ground before the “swing phase,” swinging the foot forward into the next step.

“The transition between mid-stance where the foot is underneath the runner and terminal stance where they’re pushing off and driving their run forward—this is the time in the gait cycle where the carbon fiber plate is most influential,” Brough says. The springy midsole foam and the rigid carbon plate help to magnify that push-off. “With propelling the runner forward, we see an improvement in running economy,” she says.

Additionally, lactate threshold (also known as anaerobic threshold, the point where your body can no longer clear lactate during endurance training and begins to fatigue) and VO2 Max (the maximum amount of oxygen your body can use during exercise) are important. Essentially if the shoes require less energy to run with, you’re more able to channel your VO2 max and lactate threshold into intensity to run a bit faster. “That’s what gives you your higher speed and faster finish time,” Hoogkamer says.

The Super Shoe Lab Test Protocol

The system I’m running on in Boston at Puma’s Nitro Lab is going to measure more than just running economy, according to Laura Healey, Puma’s Senior Research & Sports Science Manager, Footwear Innovation who is leading the trial. The Treadmetrix unit is equipped to measure the force of my footfalls, which will yield data on my step length, propulsion, and more.

The testing protocol is simple—and it’s the same industry-standard approach used since that 2018 study. I start with a brief warmup wearing a pair of “normal” shoes to get acclimated to the treadmill setup. After that, I slide on another model, a premium race day shoe from one of Puma’s competitors. Healey sets the tread to a 7:45 per mile pace, which is about where I estimate my speed would be for a marathon given my current level of fitness. I run for five minutes in the competitor shoes, rest briefly, then change into the Fast-R Nitro Elite 3, and run for another five minutes at the same pace.

That cycle repeats for three rounds, meaning that by the end of the test, I’ve run about 30 minutes in total at marathon pace. I’m sweaty, but I feel fresh, not like I just accumulated nearly six miles of fairly speedy training. Both pairs of sneakers are fun to run in—they’ve got bouncy foams and their dramatic midsole shapes lead me to roll through each stride—and I’m not exactly sure what I’ll learn from the trial.

My Test Results

After I’ve had a chance to cool down, the Nitro Lab team walks me through the results. Puma’s shoe felt springy on the tread, but since I was essentially running in place, it was tough to tell just how active it was within my stride cycle.

The data presented to me is clear: I was a more efficient runner wearing the Fast-R Nitro 3. My running economy was 3.7 percent better in the three segments I wore the Puma shoe than when I wore the competitor’s, a margin that could result in fairly significant speed gains on the road. Healey explains to me that if I were to apply that number to my half marathon PR of 1:29, the (theoretical) performance improvement would result in a time of 1:26:21, almost three minutes difference. Race day milestones are sometimes decided by seconds—so a three minute swing is major.

My results are a sample of one, but Hoogkamer’s team at UMass-Amherst also put the super shoes through their paces for a new study (notably, sponsored by Puma), which is awaiting peer review. They reported a 3.6 percent improvement in running economy with the Fast-R Nitro 3. But now that I understand the science behind running economy better, I’m more interested in how the shoes perform outside the lab (and you can read more about that in my review here). There are so many factors that contribute to how I run when I’m striving to break a PR—how well I’ve slept, how much I trained to prepare, if I’ve dialed in my fueling—so I’d rather see how I’m able to run when I don’t have a tube in my mouth.