Do Super Shoes Give Regular Marathoners a Performance Boost?
It’s no coincidence that running records have been falling in droves in the era of super shoes. While researchers still may not be able to fully explain how the technology works, they have shown that the ultra-compressible foam, curved carbon-fibre plate, and rockered geometry that first appeared in the Nike Vaporfly 4% in 2017 provide competitive runners a 2.7–4.2 percent boost in running economy. In other words, thanks to these shoes, runners need 2.7-4.2 percent less energy to run the same pace—meaning that they can conserve that energy to run farther or expend it to run faster.
One caveat is that, until now, super shoes have been tested only at running speeds of 7:26/mile or faster. Translated into marathon times, that means the science is applicable to someone who runs a marathon in 3:15 or faster—a feat accomplished by only 21 percent of the 2021 Boston Marathon field.
However, new research has finally emerged that looks at whether the majority of runners get an edge from super shoes. The answer: probably yes, but less.
Research for Non-Elites
Dustin Joubert, Ph.D., a kinesiology professor at St. Edward’s University in Austin, Texas, likes to do research, in his words, 'for the people.' This is how he came to conduct a study looking into whether super shoes, specifically the Nike ZoomX Vaporfly Next% 2, confer the same running economy advantage to athletes who run at slower paces.
'There’s a lot of people who don’t fit under the umbrella of the speeds that have been tested in all this laboratory research, and a lot of people are asking: Should I spend my money on this? Do they work for slower people?' said Joubert. 'That was the next logical question to me.'
To answer the question, Joubert and his colleagues recruited 16 runners – eight men and eight women with prior-year 5K PBs averaging 19:06 and 20:18, respectively – and had them complete two sets of four 5-minute running reps on a treadmill. Each runner ran one set at a 12 kilometres/hour pace (8:00/mile, which would be marathon pace for a runner with a 5K PB of 22:15), and the other set at 10K/hour (9:40/mile, which would be on the slower end of easy pace for that same 22:15 5K runner). Within a given set, the runners tested two different shoes: they ran one 5-minute rep in an experimental carbon-plated shoe, the Nike ZoomX Vaporfly Next% 2, and the other rep in a control shoe, the Asics Hyper Speed. Then, the runners repeated the reps but reversed the order in which they wore shoes (e.g., Asics first, then Nike).
The researchers chose the Asics Hyper Speed as the control shoe because it lacks the technology of the Vaporfly (carbon plate and advanced foam) but matches its mass. This was an important variable to match because mass affects running economy; a heavier shoe will require more energy to move and could therefore confound results. One earlier study compared the Vaporfly to runners’ everyday training shoes, but most regular training shoes are more than 100 grams (3.5 ounces) heavier – the equivalent of about 40 pennies. Imagine lifting those pennies 55,000 times (the average number of steps in a marathon, for men; women take about 63,000 steps). That would require quite a bit more energy.
Economy Advantages for 3:30–4:15 Marathoners
The new study found that, on average, running economy was better in the Vaporfly than in the Hyper Speed. However, at these slower speeds, the improvements were smaller than at faster speeds: runners gained just 1.4 percent in running economy at 8:00/mile pace and 0.9 percent at 9:40/mile pace, compared to the 2.7–4.2 percent advantage runners gained at speeds of 7:26/mile or faster. (And, as we’ll see below, even those improvements came with a caveat.)
Joubert speculates that the reason for this difference comes down to how the foam in the shoes is working. Much of the running economy advantage comes from compressing the compliant/resilient foam in the shoes and then having that energy returned as the foam springs back. A faster runner who is generating larger ground reaction forces will compress the foam more than a slower runner who, because of their speed, isn’t generating as much ground reaction force.
'The shoe is not creating energy for you; it’s only giving back what you put into it,' explained Joubert.
Not Everyone Benefits
Before you decide 'an advantage is an advantage,' there is one other finding from this study that should give runners pause. While the results from the 16 test subjects showed a 0.9–1.4 percent average improvement in running economy, one third of the participants actually showed worse running economy when they ran at the 9:40/mile speed in the Vaporflys, compared to the control shoe. This finding diverges from the results of testing done on the Vaporflys at faster speeds, where runners experienced varying degrees of running economy improvement, but no one saw a detriment.
One possible reason has to do with the Vaporfly’s carbon plate. Research has shown that increased longitudinal bending stiffness, or the rigidity of a shoe underfoot, helps to improve running economy at faster speeds by reducing the amount of energy your foot requires as you land and push off from the metatarsophalangeal joint (where your foot connects with your toes). Joubert hypothesizes that, at slower speeds, the stiff carbon plate might stop saving runners energy and instead create a need for more energy in order to get 'up over' the plate.
'If the plate’s really stiff, maybe at these slower speeds that’s an impairment to economy,' Joubert said.
Nathan Brown, a doctor of physical therapy at Pineries Running Lab in Stevens Point, Wisconsin, and senior contributor at Doctors of Running, said that this finding in particular helps to reinforce the shoe selection guidance he already offers his patients and the runners he coaches.
'If your goal of picking a shoe for race day is to get faster, but there’s a 30% chance that you get worse, I care more about finding the shoe that you like to run in than the shoe that may or may not give you a benefit,' said Brown.
So, Should You Wear Super Shoes?
If you’re an 8:40-9:00/mile marathoner, what should you do? Do you gamble on being in the 66% of responders and plunk down your cash for a pair of super shoes? Or do you stick with what you have?
Footwear is ultimately a personal decision, so here are a few more points to consider.
Choose a shoe that’s comfortable
If a super shoe feels uncomfortable, that might be an indicator that the shoe won’t help you make the economy gains you’re seeking. Joubert guesses that the comfort of your shoes could affect biomechanical aspects of your race-day performance, including economy. 'I think if a shoe is uncomfortable, it’s probably not going to be economical,' he said.
Brown emphasises focusing on comfort and confidence in a race-day shoe rather than 'carbon [plate] or no carbon'. To determine whether it’s comfortable, Brown recommends trying your racing shoe in a few workouts and, if your goal race is a marathon, a few long runs in advance of race day.
'You want to feel comfortable [in the] shoe and confident psychologically,' he said. 'To know what to expect on a long run from your race-day shoe can be a big deal for performance.'
Don’t wear a super shoe (or any one shoe) for every single run
Heather Knight Pech, a decorated masters runner and coach for McKirdy Trained and Knight Training, tells every one of her athletes, from high schoolers to masters runners, to invest in a minimum of three pairs of running shoes: a trainer (eg Saucony Triumph), a lightweight trainer (eg Hoka Mach 5), and a race-day shoe (eg Nike Zoom Alphafly Next% 2). She then has them rotate among these shoes for several reasons.
First, it decreases injury. Research has shown that runners who rotate their shoes decrease their injury risk by 39 percent compared to runners who wear the same pair for every run.
'Running is a repetitive motion, so you avoid overloading any one muscle, bone, or tendon,' said Pech. 'And on the flip side, you’re simultaneously strengthening other structures by rotating your shoes.'
In his physical therapy practice, Brown has found that super shoes tend to reduce the loading on lower leg structures like the Achilles tendon and calf. As a result, he’s noticed a trend in repetitive stress injuries further up the chain, to the hamstrings and hip flexors, in runners who wear that shoe for most or even all of their runs.
The second reason Pech advises runners to rotate shoes is that it forces them to decide between shoes for a given run, which helps them gain a better sense of self-awareness. 'We should be very dialed in to how we feel – that’s part of running training and racing,' said Pech. The saying she repeats is: different shoes for different runs for different days.
Look at a variety of styles and brands.
The Nike Vaporfly was the first high-stack carbon-plated shoe on the market, and as a result, it is arguably the most well known. Most brands now have a similar shoe, and while research shows they’re not yet up to par when it comes to running economy, that doesn’t mean different shoes won’t work better for certain runners based on foot anatomy, running stride, and even pure preference.
Pech points out that the Nike Vaporfly is a very high, very narrow, very bouncy shoe. The Saucony Endorphin Pro, on the other hand, she describes as 'more stable underfoot, with firmer foam. It’s great for runners who want to feel the ground'. Meanwhile, the Asics Metaspeed Sky+, which is also slightly wider underfoot than the Nike Vaporfly, offers two versions between which runners can choose based on their running style: cadence (increasing their turnover) or stride (increasing their stride length).
'I think they’ve all caught up, in that, now, there are different shoes for different people,' said Pech.
Remember: economy isn’t everything.
While running economy does influence running performance, it’s only one small part; how well you eat and sleep, your level of anxiety, how consistently you trained, how well you tapered, and numerous other factors have an equal, if not greater effect on the time you ultimately run in any given race.
Therefore, if you’re a 3:30–4:15 marathoner and don’t want to shell out the money or risk finding yourself in the 33% 'anti-responder' group, double down on some basics like pre- or post-run nutrition or even just sleep. Plus, when you beat your Vaporfly-wearing counterparts, you’ll never have to ask, 'Was it the shoes?'
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