Supercritical foam explained: The technology reshaping every running shoe in 2026

If you have bought a running shoe costing more than £120 in 2026, there is a very good chance it contains supercritical foam. This class of midsole material — which includes PEBA-based foams, nitrogen-infused compounds, and other advanced formulations — has rapidly become the industry standard for mid-range and premium running shoes, displacing the ethylene vinyl acetate foam that dominated the market for decades.

The term supercritical refers to the manufacturing process, not the material itself. In supercritical foaming, a gas — typically nitrogen or carbon dioxide — is dissolved into a polymer under extreme pressure and temperature, then rapidly released to create millions of tiny, uniform air pockets within the foam. The result is a material that is lighter, more resilient, and significantly more responsive than conventionally foamed EVA. Energy return figures for supercritical PEBA foams typically range from 85 to 90 per cent, compared with 55 to 65 per cent for standard EVA.

The practical benefits for runners are substantial. Shoes with supercritical foam midsoles feel noticeably bouncier underfoot, maintain their cushioning properties over significantly more miles, and weigh less at the same stack height. Where an EVA-based trainer might feel dead after 400 miles, a supercritical foam shoe can maintain its performance characteristics past 500 or even 600 miles, making the higher upfront cost more palatable when measured on a per-mile basis.

Every major brand now offers multiple models with supercritical foam technology. Nike's ZoomX, Adidas's Lightstrike Pro, New Balance's FuelCell, Asics's FF Blast Turbo, and Saucony's PWRRUN PB are all variations on the same fundamental concept. The differentiation between brands now lies less in the foam itself and more in how it is combined with plate geometry, upper design, and outsole configuration. For runners navigating the crowded shoe market, understanding supercritical foam is the single most useful piece of knowledge for making informed purchasing decisions in 2026.