Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Canada.
J Sports Sci. 2024 Aug;42(15):1432-1438. doi: 10.1080/02640414.2024.2394746. Epub 2024 Aug 29.
The Nike Vaporfly 4% (VP4) shoe is popular due to its unique design and reported performance benefits. However, the underlying mechanisms responsible for the improvements remain unclear. One proposed mechanism is the teeter-totter effect. This study aimed to 1) experimentally test the teeter-totter theory by estimating the teeter-totter moment (M) in the VP4 compared to a flat shoe (CONTROL) and 2) quantify the change in the anterior-posterior position of the centre of pressure (Δx) in the VP4 compared to the CONTROL. Plantar pressures and high-speed video were recorded from 15 runners in two shoe conditions. The VP4 generated a larger propulsion moment, M, ( = 90.46 ± 38.87 Nms; < 0.001, = 1.95), suggesting the presence of an M in the VP4 ( = 57.16 ± 24.35 Nms) when compared to the CONTROL ( = 33.30 ± 14.52 Nms). Δx was greater in the VP4 (Δx = 9.48 ± 6.08 mm; < 0.001, = 2.07) compared to the CONTROL (Δx = 0.54 ± 0.67 mm). This study provides a methodological proof-of-concept for the teeter-totter theory. The findings highlight the possibility of a teeter-totter effect resulting in greater heel propulsion while running in an AFT shoe construction, assuming a constant muscle moment and pivot point.
耐克 Vaporfly 4%（VP4）鞋因其独特的设计和据称的性能优势而广受欢迎。然而，其性能提升的潜在机制尚不清楚。一种提出的机制是跷跷板效应。本研究旨在：1）通过估计 VP4 与平底鞋（CONTROL）相比的跷跷板力矩（M），实验性地测试跷跷板理论；2）量化 VP4 与 CONTROL 相比，中心压力（Δx）前后位置的变化。从两种鞋类条件下的 15 名跑步者记录了足底压力和高速视频。VP4 产生了更大的推进力矩 M（=90.46±38.87 Nms； <0.001， =1.95），这表明 VP4 中存在 M（=57.16±24.35 Nms），与 CONTROL（=33.30±14.52 Nms）相比。与 CONTROL（Δx=0.54±0.67 mm）相比，VP4 中的 Δx 更大（Δx=9.48±6.08 mm； <0.001， =2.07）。本研究为跷跷板理论提供了方法学上的概念验证。研究结果表明，在 AFT 鞋结构中跑步时，假设肌肉力矩和枢轴点不变，跷跷板效应可能导致更大的脚跟推进。
