Midsole foam compliance is a greater contributor to running economy, biomechanics, and perception than foam resilience or stack height in advanced footwear technology in male runners
Year: 2026
Type: article
Abstract: Advanced footwear technology (AFT) includes a tall stack of compliant, resilient, low-density foam. Despite the unclear effect of stack height on running economy, advanced footwear commonly approaches the World Athletics 40 mm limit. Additionally, compliant and resilient foams may improve running economy by up to 2%, but studies isolating compliance and resilience are few. The goal of this study was therefore to examine the independent effects of altering these three principal determinates of footwear energy return on running economy, biomechanics, and perception. Twelve experienced male runners ran at a self-selected steady-state speed in four weight-matched footwear in randomised, mirrored order: a control AFT and experimental footwear with reduced compliance, resilience, or midsole stack height. Compared to the control AFT, reducing midsole compliance, which increased compression stiffness by 24.2%, significantly worsened running economy by 1.3%. This energetic change was accompanied by reduced stride length, vertical leg stiffness, peak vertical ground reaction force, peak propulsive force, vertical impulse, and peak knee extension, and greater duty factor and braking impulse. It was also perceived as more rigid, noticeable, firm, and high impact and less enjoyable and less comfortable. Reducing resilience by 11.4% or stack height by 10 mm both resulted in numerous biomechanical changes accompanied by non-significant changes in running economy. Reduced stack height also resulted in numerous perceptual differences, while reduced resilience did not. This study demonstrates that midsole compliance is a key determinant of running economy, biomechanics, and perception in AFT, while reductions in midsole resilience or stack height produce more limited effects.
Source: Footwear Science
Institution: New Balance (United States)
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7137285084