Wrbaskić N, Dowling J J
Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4K1.
Clin Biomech (Bristol). 2007 Feb;22(2):230-8. doi: 10.1016/j.clinbiomech.2006.09.006. Epub 2006 Dec 4.
To determine the behaviour of the human foot during in vivo loading and unloading.
Fluoroscopic imaging was used to investigate the movement of the bones and 13 skin markers during loading and unloading for the medial aspect of the left foot. A foot-pressure measuring system was compared with a force plate used to gather kinetic information, simultaneously. Four male and two female subjects performed three tasks that mimicked jumping, walking, and sprinting. Two-dimensional vector displacements were calculated between bone landmarks over time. Foot rigidity was assessed by a 5 mm length variability threshold determined as the difference between the third and first quartiles of the data set.
The displacement between the first metatarso-phalangeal joint and distal aspect of the calcaneous varied more than the 5 mm threshold. A new foot model was developed which included three rigid segments joined together by hinge joints located at the first metatarso-phalangeal joint and between the anterior talus and navicular. The comparison between skin mounted markers and bone landmarks yielded a range of correlation slopes close to 1.00 for both the x- and y-directions. Foot pressure and force plate comparisons were promising (%RMS(error) approximately 10%) for the vertical ground reaction forces but not so for the centres of pressure (%RMS(error) up to 50%).
A multi-segment foot model is required to better represent the behaviour of a human foot. No consistent skin marker movement was determined. Better pressure distribution devices need to be developed to determine more accurate foot kinetics. Precise foot kinematics are required in order that accurate ankle moments and reaction forces be determined for the purpose of assessing foot and ankle function.
确定人体足部在体内加载和卸载过程中的行为。
使用荧光透视成像来研究左脚内侧在加载和卸载过程中骨骼和13个皮肤标记物的运动。将足部压力测量系统与用于同时收集动力学信息的测力板进行比较。四名男性和两名女性受试者执行了三项模仿跳跃、行走和冲刺的任务。计算随时间变化的骨骼标志点之间的二维矢量位移。通过将数据集的第三四分位数与第一四分位数之差确定为5毫米长度变异性阈值来评估足部刚性。
第一跖趾关节与跟骨远端之间的位移变化超过5毫米阈值。开发了一种新的足部模型，该模型包括三个刚性节段，通过位于第一跖趾关节以及距骨前部与舟骨之间的铰链接合在一起。对于x和y方向，皮肤安装标记物与骨骼标志点之间的比较产生了一系列接近1.00的相关斜率。足部压力与测力板在垂直地面反作用力方面的比较前景良好（均方根误差百分比约为10%），但在压力中心方面则不然（均方根误差百分比高达50%）。
需要一个多节段足部模型来更好地表示人体足部的行为。未确定一致的皮肤标记物运动。需要开发更好的压力分布装置来确定更准确的足部动力学。为了评估足踝功能，确定准确的踝关节力矩和反作用力需要精确的足部运动学。
