ECSS Paris 2023: OP-BM25
INTRODUCTION: Running in advanced footwear technology (AFT) has repeatedly been demonstrated to improve running economy (RE) on average compared to traditional running shoes [1, 2]. The range in individual improvements, however, is broad, with some studies even showing no or negative effects [3]. A recent framework [4] proposes that besides the purely mechanical advantages of AFT materials, the biomechanical interplay between athlete and shoe determines part of the shoes' effectiveness. Yet, no study has investigated individual running biomechanics across various AFT models in relation to changes in RE. Therefore, this study aimed to identify biomechanical factors associated with intra-individual changes in RE when running in various AFT models using a within-subject design. METHODS: Twenty-two competitive distance runners (11 female, age: 33.1±6.2 years, BMI: 21.0±1.7 kg/m2) completed three 5-minute running bouts at their individual marathon pace (10.9–19.5 km/h) on an instrumented motorized treadmill in randomized order. They wore three standardized AFT models (Asics Metaspeed Sky+, Nike Alphafly Next% 2, Puma Fast-R Nitro Elite v1). Respiratory gas exchange was measured continuously, and RE was defined as the energetic cost of transport (eCoT) [5]. Three-dimensional kinematics and spatiotemporal variables were acquired using a 12-camera motion capture system and an embedded pressure plate. Akaike Information Criterion-based model averaging, and least absolute shrinkage and selection operator (LASSO) were used with linear mixed-effects models to identify biomechanical parameters associated with intra-individual changes in RE across AFT models. RESULTS: Both model selection strategies identified ground contact time (GCT) as the only robust predictor of intra-individual RE changes. In the final model, shorter GCT was significantly associated with lower eCoT (β=0.025, 95% CI [0.010, 0.040], p=0.002), reflecting approximately 1% improvement in RE per 4 ms decrease in GCT. Step rate and peak metatarsophalangeal joint flexion showed high relative model importance (sum of Akaike weights) but were not statistically significant (both p>0.05). No group-level differences in eCoT were found between AFT models (p=0.246). CONCLUSION: Reduced GCT was the only significant biomechanical predictor of improved RE across three AFT models. The absence of group-level RE differences highlights substantial inter-individual variability, suggesting that none of the AFT models used here were universally optimal. These findings may inform individualized footwear selection for competition. Future research should further investigate the interaction of AFT properties and individual biomechanics to advance our understanding of the individual responses to AFT. 1. Hoogkamer W et al. Sports Med 2018;48:1009–1019. 2. Hunter I et al. J Sports Sci 2019;37:2367–2373. 3. Knopp M et al. Sports Med 2023;53:1255–1271. 4. Connick MJ, Lichtwark GA. J Appl Biomech 2025;41:1–7. 5. Péronnet F, Massicotte D. Can J Sport Sci 1991;16:23–29.
Read CV Dominik FohrmannECSS Paris 2023: OP-BM25