PEBAX Shoes get slower over time – Sorry, Nike
Víctor Rodrigo-Carranza et al. have released a study analysing the energy cost of supershoes but this time around they’ve looked at the difference between supershoe sole materials both when the shoes are new AND after 450km/300 miles of use.
More: Arkema (PEBAX)
More: EVA
Science Source: Wiley
Tip: Save your race shoes for races.
Tip: Perhaps convert your race shoes to training shoes after a hundred miles or so and buy some more supershoes. Make Nike happy.
Results
There were significant differences in RE between conditions (p = 0.01; n2 = 0.17).
There was a significant increase in energy cost in the worn PEBA condition compared with new (15.21 ± 1.01 and 14.87 ± 0.99 W/kg; p < 0.05; ES = 0.54), without differences between worn EVA (15.13 ± 1.14 W/kg; p > 0.05), and new EVA (15.15 ± 1.13 w/kg; ES = 0.02). The increase in energy cost between new and worn was significantly higher for the PEBA shoes (0.32 ± 0.38 W/kg) but without significant increase for the EVA shoes (0.06 ± 0.58 W/kg) (p < 0.01; ES = 0.51) with changes in step frequency and step length. The new PEBA shoes had lower energy cost than the new EVA shoes (p < 0.05; ES = 0.27) with significant differences between conditions in contact time.
Conclusion
There is a clear RE advantage of incorporating PEBA versus EVA in an AFT when the models are new. However, after 450 km of use, the PEBA and EVA shoes had similar RE.
Last Updated on 25 January 2026 by the5krunner
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tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors.
Aha, that explains my consistent running deterioration over the last 4 or 5 years. Phew!
Anecdotally, I found my Nike Next% were good for a single season, racing one each for 5km, 10km, half and full Marathon. After the marathon, they didn’t feel as fast.
I wonder what the actual difference would be scientifically after just 80 – 90km, My guess would be that the degradation would be much higher when new.
that sounds anecdotally right to me.
I’m wearing my ‘ancient’ vaporflys now as my round-the-house trainers. they are still nicely springly and comfortable although the sole is just about starting to fall apart. the point of saying that is that they do feel like they should still be runnable in…but this sciecne states they wont be as fast.
the degradation must be in the chemical structure of the foam. ‘springiness’ will be a property that is caused by some chemical bond or molecular structure (A level chemistry…I should know!!! but have long forgotten)