Influence of different midsole foam in advanced footwear technology use on running economy and biomechanics in trained runners

Abstract

BackgroundEthylene and vinyl acetate (EVA) and polyether block amide (PEBA) are recently the most widely used materials for advanced footwear technology (AFT) that has been shown to improve running economy (RE). This study investigated the effects of these midsole materials on RE and biomechanics, in both fresh and worn state (after 450 km).MethodsTwenty‐two male trained runners participated in this study. Subjects ran four 4‐min trials at 13 km‧h−1 with both fresh EVA and PEBA AFT and with the same models with 450 km of wear using a randomized crossover experimental design. We measured energy cost of running (W/kg), spatiotemporal, and neuromuscular parameters.ResultsThere 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.ConclusionThere 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.

Effects of longitudinal bending stiffness and midsole foam on running energetics

“…Worobets et al (2014) observed a 1% running economy improvement from EVA to TPU (thermoplastic polyurethane) midsole foam. Rodrigo- Carranza et al (2024) studied separate AFT shoe models, both with similar, but not identical, carbon fiber plate, tall stack height and rocker geometry, and with different midsole foams and found a 1.8% better running economy in the shoes with (fresh) PEBA foam than in the shoes with (fresh) EVA foam. Similarly, we observed a 1.0% improvement in running economy on average between EVA and PEBA foam, while using identical shoe models, controlling all other variables.…”

Relationship Between Advanced Footwear Technology Longitudinal Bending Stiffness and Energy Cost of Running

“…There is a growing body of literature indicating that the new more resilient and compliant midsole foams are of greater importance than increased LBS in improving RE when using AFT [20, 35, 36]. Recently, we showed on separate occasions that AFT shoes with a curved carbon fiber plate and a highly resilient and compliant midsole improved RE by 1%–2% over shoes with a curved carbon fiber plate and traditional midsole [37, 38]. It may be that the ~2.5% improvement from the Stiff versus Control condition in the current study resulted from a ~ 1% improvement from increased LBS (similar to those reported in previous studies [14, 15]) and the remainder of the improvement from using more compliant and resilient midsole materials in combination with the curved carbon fiber plate.…”

Relationship between advanced footwear technology longitudinal bending stiffness and energy cost of running

“…There is a growing body of literature indicating that the new more resilient and compliant midsole foams are of greater importance than increased LBS in improving RE when using AFT (Healey & Hoogkamer, 2022;Kram, 2022). Recently, we showed on separate occasions that AFT shoes with a curved carbon fiber plate and a highly resilient and compliant midsole (PEBA) improved RE by 1-2% over shoes with curved carbon fiber plate and traditional midsole (EVA) (Lino et al, 2023;Rodrigo-Carranza, Hoogkamer, González-Ravé, Horta-Muñoz, et al, 2023). It may be that the ~2.5% improvement from the Stiff versus Control condition in the current study resulted from a ~1% improvement from increased LBS (similar to reported in previous studies (Oh & Park, 2017;Roy & Stefanyshyn, 2006)) and the remainder of the improvement from using more compliant and resilient midsole materials in combination with the curved carbon fiber plate.…”