Leg stiffness during running in highly cushioned shoes with a carbon-fiber plate and traditional shoes

• Published in: Gait & posture 2022-06, Vol.95, p.9-14
• Main Authors: Hata, Keiichiro, Noro, Hiroaki, Takeshita, Tomonari, Yamazaki, Yohei, Yanagiya, Toshio
• Format: Article
• Language: English
• Subjects: Footwear; Leg stiffness; Running; Spring-mass model
• ISSN: 0966-6362; 1879-2219
• DOI: 10.1016/j.gaitpost.2022.03.021

Nike ZoomX Vaporfly (NVF) improves running economy and performance. The biomechanical mechanisms of these shoes are not fully understood, although thicker midsoles and carbon fiber plates are considered to play an important role in the spring-like leg characteristics during running. Leg stiffness (kleg) in the spring-mass model has been commonly used to investigate spring-like running mechanics during running. Does kleg during running differ between NVF and traditional (TRAD) shoes? Eighteen male habitual forefoot and/or midfoot strike runners ran on a treadmill at 20 km/h with NVF and TRAD shoes, respectively. kleg, vertical oscillation of the center of mass (∆CoM), spatiotemporal parameters, and mechanical loading were determined. kleg was 4.8% lower in the NVF shoe condition than in the TRAD condition, although no significant difference was observed. ∆CoM was not significantly different between shoe conditions. Spatiotemporal parameters and mechanical loading were also not significantly different between shoe conditions. The NVF shoe is well known as improving the running economy and running performance for the cause by characteristics of better spring function. Contrary to expectation, kleg and other parameters were not significantly different during running in the NVF compared to TRAD shoe at 20 km/h. These findings indicate that well-trained runners’ spring-like running mechanics would not alter even if wearing the NVF shoes. •Leg stiffness was not significantly different.•Spatiotemporal parameters were all not significantly different.•Impact force and loading rate were not significantly different.