Author(s): XUELIAN, M., YAN, X.Y., SHI, H.J., YANG, F., LI, H.J., Institution: BEIJING SPORT UNIVERSITY, Country: CHINA, Abstract-ID: 406

INTRODUCTION:
Shoe cushioning and energy return are key mechanical properties of modern running footwear, commonly intended to influence running biomechanics [1]. Despite the prevailing view that increased cushioning attenuates impact loading and that higher energy return reduces joint mechanical demand, empirical evidence is inconsistent [2,3], and the quantitative links between mechanically measured shoe properties and running biomechanics remain limited. Therefore, this study aimed to quantify the relationships between mechanical shoe cushioning and impact loading, evaluate the effects of forefoot energy return on lower limb joint kinetics, and examine whether these relationships are modulated by running speed.
METHODS:
Twelve male recreational runners performed overground running at three speeds (8, 10, and 12 km·h⁻¹) while wearing ten commercially available running shoes without stiff plates. The shoes spanned a wide range of mechanically quantified rearfoot cushioning (Peak G: 6.9–9.5 g) and forefoot energy return (54.0–69.1%). Ground reaction forces and lower limb kinematics were collected for three valid right foot ground contacts in each shoe condition. Impact peak, time to impact peak, vertical average loading rate (VALR), and lower limb joint moments and work were calculated. Linear mixed-effects models were used to examine the effects of shoe mechanical properties and running speed.
RESULTS:
Lower Peak G was associated with reduced VALR (estimate = 3.42 BW·s⁻¹, 95% CI [2.58, 4.25], p < 0.001). In addition, higher Peak G was negatively associated with time to impact peak (estimate = –2.15 ms, 95% CI [–2.52, –1.79], p < 0.001), whereas no significant associations were observed for impact peak. Conversely, higher forefoot energy return was associated with increased ankle plantarflexion moment and joint work (all p < 0.05), with no significant associations observed at the knee or hip joints. All observed associations were consistent across the tested running speeds.
CONCLUSION:
The quantified Peak G–VALR relationship provides a practical biomechanical reference for evaluating shoe cushioning. Lower Peak G was consistently associated with reduced VALR across speeds, suggesting that shoes with sufficient cushioning may help maintain impact loading below proposed injury-risk thresholds [4]. In contrast, the observed association between forefoot energy return and joint kinetics was contrary to prior studies [3], indicating that greater shoe energy return may not necessarily translate into reduced joint mechanical demand. Overall, this study bridges the gap between mechanical testing and biomechanical response, providing a comprehensive quantitative framework to guide future footwear evaluation and design.
References
[1] Nigg, B. M., et al. (2023). Footwear Science, 15(2), 133-143.
[2] Fife, A., et al. (2023). Footwear Science, 15(2), 103-112.
[3] Matijevich, E. S., et al. (2024). Sports Biomechanics, 24(6), 1495-1513.
[4] Cheung, R. T., & Rainbow, M. J. (2014). Hum Mov Sci, 34, 120-127.