Super Shoes Or Super Placebo?

Thinking of buying a pair of Nike Vaporfly's (pictured above) for your next racing shoe? Or another super shoe from another brand? Here's a really interesting study I read on super running shoes.

Researchers in that study (Hebert-Losier et al, 2025) recruited 24 female recreational runners. All ran in Nike's Vaporfly Next% 2.

Here is what is so interesting, the shoe was not changed or manipulated. It was how the shoe was described. For the first shoe, the narrative was a "super shoe" description. carbon plated, energy return foam, elite level technology and expensive ($400).

For the other pair, a "basic/ knock-off" (or counterfeit) description with  no carbon plate, standard foam, lower price, ($100) and the idea that elite runners will not race in them.

Nothing changed in the shoe, just the "story" or description of the shoe.

All the participants did four 6-minute treadmill runs at 10km/h on a 1 percent incline. The researchers measured their running economy (V02 and energy cost). Cadence and contact time on the ground and perceptual responses were also investigated. These include comfort, enjoyment of run, ease, expected performance and perceived injury risk.

When the runners thought they were running with the Super shoes, perception changed noticeably. Reported comfort was significantly higher. They also felt running was easier and more enjoyable. Expected performance was higher and their perceived injury rate was lower.

To summarize, the subjective experience of running improved even though the shoes used were exactly the same.

What about the objective measures? There were NO significant differences in running economy, oxygen consumption, lactate responses or even biomechanically.

Whilst running at 10 km/h pace for 6 minutes, belief alone did nothing to translate into measurable physiological or even biomechanical differences.

Does this mean you don't have to buy super shoes for your next attempt to beat your marathon personal best? 

Personally I don't think so. 6 minutes at 10 km/h pace using recreational runners may not be totally accurate. It shows that expectation plays a big role in how running feels even though performance metrics remained unchanged.

Comfort, confidence, enjoyment and perceived safety matter so one can train consistently and push themselves harder when there is less fear of injury. These may not show in data measuring running economy, but may still influence outcomes over time.

The message for runners is NOT that they do not need to buy super shoes. Instead it's that shoes cannot replace training and price tags do not guarantee performance. Perception changes a runner's experience, even when physiology does not change.

Technology helps sometimes. Sometimes the story helps too.

So are you buying Nike's Vaporfly or Decathlon's Kiprun (pictured above)?

Reference

Hebert-Losier K, PfisterA, Finayson SJ et al (2025). Are Super Shoes A Super Placebo? A Randomised Crossover Trial In Female Recreational Runners. Footwear Sc. 17(2): 79-88. DOI: 10.1080/19424280.2025.2458330

How Long Does Your Running Shoe Last?

Picture from Run Repeat

Ever wondered how long before you need to change your running shoes? A bit of history on midsole technology. Previously, the midsoles in running shoes were all made with ethylene-vinyl acetate (or EVA). Then Adidas managed to secure (Adidas bought the technology from BASF) their Boost midsole out of thermoplastic polyurethane (TPU) in 2013 which led to many marathon world records falling. In 2017, Nike's super shoe, the Vaporfly, was made of polyether block amide (PEBA) and it is still the current dominant midsole.

Previous anecdotal evidence and hearsay suggest EVA midsole running soles tend to last between 300 to 500 miles (480 to 800 km). There was an older study supporting this information (Cook et al, 1985). The researchers measured shoes shock absorption at frequent intervals between 0 to 500 miles. 

A machine was used to simulate running impact as well as 2 vounteers who actually ran 500 miles (pictured above). The 2 human volunteers show similar patterns compared to the machine (see diagram). Human testing showed that EVA midsole shoes retained 80 percent of shock absorption after 150 miles (240 km) and 70 percent after 500 miles (800 km). The curve then flattens out between 300 to 500 miles which is probably where we get shoe lifespan information from.

More recently, a bunch of researchers teamed up with the brand On and manufactured prototype running shoes that were almost identical (Rodrigo-Carranza et al, 2023). One had the new PEBA super foam while the other had the traditional EVA midsole. 

Shoe testing from Rodrigo-Carranza et al (2023)

Both versions also had a curved carbon fiber plate. They tested the shoes before and after 280 miles (448 km). 22 runners performed a running economy test to measure how much energy they used at a given pace, once in fresh shoes, once with pre-worn shoes. The researchers themselves actually ran 280 miles (448 km) in each pair of shoes to pre-wear them for the research!

The researchers found that the new super foam did lose their powers quicker. In fact they were no better than the traditional EVA midsole when they did. A key finding was that energy consumption while running with the new PEBA midsole shoe was 1.8 percent less than using the new EVA shoe. This strengthens the case that the super foam itself is more important ingredient since both versions of the prototypes had carbon plates in them.

Another key finding was that after 280 miles (448 km), there was no significant difference between the 2 shoes. The EVA did not lose anything while the PEBA super foam shoe got 2.2 percent worse. Please note that not all PEBA foams are created equal. On's super foam may not be totally similar to Nike's and other brands.

I have not converted to super shoes yet as I do not like them stacked too high. Moreover, I currently only run 2-3 times a week and I rotate between 2 to 3 pairs of shoes with EVA and TPU midsoles. I run in them until they start to feel "flat". It is relatively easy to feel especially if one of my other newer pairs still feels supportive by comparison. I usually retire that "flat pair" from running but will still use them for walking. If you're using the PEBA foam super shoes, you may have to change them earlier.

If you are interested, have a look at Run Repeat, where infomation on a huge range of high performance super foams are available. The author, Carlos Sanchez runs 100 km a week and has run three sub 3 hours marathons. Sanchez suggests that shoe foams take more than 24 hours to 'recover' and some foams recover faster than others so you may want to rotate your running shoes to maximise comfort and shoe life.

References

Cook SD, Kester MA and Brunet ME (1985). Shock Absorption Characteristics Of Running Shoes. AJSM. 13(4): 248-253. DOI: 10.1177/036354658501300406

Rodrigo-Carranza V, Hoogkamer W, Gonzalez-Rave JM et al (2023). Influence Of Different Midsole Foam In Advanced Footwear Technology Use In Running Economy And Biomechanics In Trained Runners. Scan J Med Sci Sp. DOI: 10.1111/sms.14526