University of Calgary, Human Performance Laboratory, Calgary, AB, Canada T2N 1N4.
J Biomech. 2012 Oct 11;45(15):2680-3. doi: 10.1016/j.jbiomech.2012.08.025. Epub 2012 Sep 7.
Previously, foot torsion has been studied with respect to peak angles during athletic movements. Athletic footwear often contains a torsion element that dictates a torsion axis of the shoe. The location of the axis of rotation of the foot is, however, unknown. Therefore, the purpose of this study was to describe the torsion axis location during the stance phase of lateral cutting movements. Thirty-nine subjects performed a barefoot lateral jab and 19 subjects performed a barefoot shuffle cut. Markers were placed on the fore- and rearfoot and their movement was quantified using a 3-D video system. The torsion axis location was determined using a modified finite helical axis approach during the stance phase while the torsion angle was calculated as the amount of rotation around the torsion axis. At the beginning of the stance phase, the axis was located on the medial aspect of the foot. During the stance phase, the axis shifted towards the lateral side of the foot before the axis moved back to the medial aspect of the foot at the end of stance. For both movements significant correlations between the axis location in the vertical and medio-lateral directions and the torsion angle were found. With larger torsion (forefoot inversion) angles the axis was in a more lateral and plantar location within the foot. With this knowledge, a shoe torsion system where the shoe torsion axis location is in agreement with the foot axis location could be developed.
先前，人们已经研究了在运动动作中峰值角度的足扭转。运动鞋通常包含一个扭转元件，该元件规定了鞋的扭转轴。然而，脚的旋转轴的位置是未知的。因此，本研究的目的是描述侧向切割运动站立阶段的扭转轴位置。39 名受试者进行了赤脚横向刺拳，19 名受试者进行了赤脚滑步切割。在标记前足和后足的位置后，使用三维视频系统对其运动进行量化。在站立阶段使用改进的有限螺旋轴方法确定扭转轴位置，同时将扭转角计算为围绕扭转轴的旋转量。在站立阶段开始时，轴位于脚的内侧。在站立阶段，轴先向脚的外侧移动，然后在站立结束时回到脚的内侧。对于这两种运动，轴在垂直和中间-外侧方向的位置与扭转角之间都存在显著的相关性。扭转角较大（前足内翻）时，轴在足内更偏向外侧和足底位置。有了这个知识，就可以开发出一种与足轴位置一致的鞋扭转系统。
