Energy return in running shoes explained (2025)

TLDR

• Lab data from 500+ shoes shows energy return depends on foam material (PEBA, A-TPU, TPU) not stack height, and must combine with stiffness and weight for real performance gains.

Key Takeaways

• No strong correlation between energy return and shock absorption; ASICS Gel Nimbus 27 scores 47.7% energy return but 136 SA, while Nike Streakfly 2 hits 76.3% with only 106 SA.
• Stack height is irrelevant to bounce: a 28mm PEBA midsole can outperform a 45mm EVA midsole on energy return.
• Supershoes require three elements together: high-energy-return superfoam, carbon plate stiffener, and lightweight construction. Carbon plates without superfoam (early Hoka Carbon X 3) failed.
• Heel strikers lose rebound efficiency during stance transition; rocker geometry (HOKA Cielo X1, Adidas Terrex Agravic Speed Ultra) converts heel impact into forward momentum.
• Forefoot strikers benefit most from high energy return plus stiffness, as midsole and Achilles act as two springs in series for push-off.

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