以平台探討滑動對剪力避震之功效

Abstract

目前跑鞋多以垂直方向的避震設計為主，過去研究大部份也以垂直力作為避震能力的指標。但水平力也扮演相當重要的角色，其過大的力矩會造成肌肉震動、足底軟組織潰瘍。研究發現在較滑的運動表面上做橫向動作，可減小水平力、降低關節負荷，不過目前研究並未針對滑動表面量化有進一步的分析。目的：以滑動平台量化不同的剪力避震效果，找出最合適的滑動量，達到減少垂直與水平衝擊的效果，作為未來運動鞋開發之新方向。方法：以12位習慣腳跟著地之跑者作為受試對象，藉由四種彈簧彈性係數控制滑動程度，以赤足接受走路、慢跑及快跑之測試，收集運動學與動力學資料。結果：適度強度（k=0.067~1.99 kgf/mm）的滑動能提供更佳的垂直及水平避震能力，降低膝關節與踝關節的負荷，過多的滑動則會減小腳跟離地時的推進力，影響跑步的效率。結論：本研究可運用在運動鞋大底的設計，後跟部分使用較軟的材料或提供更多的切割，減小腳跟著地時水平方向的衝擊，而前端要增加鞋底彈性，有助於向前推進力量的提升，讓跑步更有效率，同時減少運動傷害的發生。也可針對網球、籃球等需側向動作之運動，為專項運動鞋做不同方向的滑動設計。Most designs of sports shoes focus on vertical cushion, but reducing horizontal force is also important. It would produce large moment, cause muscle vibration and impact our surface skin. Some researchers noticed sliding surface may reduce the horizontal force, but the ideal sliding amount is still unclear. Purpose: The purpose of this study was to provide different sliding effects by using different stiffness of springs to determine the ideal amount of sliding which can postpone the impact occurred and reduce both vertical and horizontal forces. Methods: 12 participants volunteered for this study, each participant was asked to perform walking, jogging and running on all four sets of springs in randomized order. Kinetic and kinematic data were calculated in this study. Results: Appropriate stiffness of springs (k=0.067~1.99 kgf/mm) could provide better vertical and horizontal cushion and reduce joint loading. But lower stiffness of springs may decrease the power during push off, influence the efficiency of running. Conclusions: To apply our findings on outsole design, we can use softer materials or provide more cuttings on rear foot, to reduce the impact during heel strike. And provide appropriate stiffness on the front forefoot to raise running speed. And try different movements to apply on more kinds of sports in future study.