Brady R A, Pavol M J, Owings T M, Grabiner M D
Biomedical Engineering Center, The Ohio State University, OH, USA.
J Biomech. 2000 Jul;33(7):803-8. doi: 10.1016/s0021-9290(00)00037-3.
The purpose of the present study was to induce slips in healthy subjects as a means to determine if recovery from an induced slip is possible under conditions in which the displacements and velocities of the slipping foot exceed the generally accepted limits of 10cm and 50cm/s, respectively, and to determine if there are gait-related variables that predispose an individual to falling after a slip. Thirty-three young and barefoot adults, protected by an instrumented safety harness, were subjected to a single slipping trial following a series of unperturbed walking trials. The slip was induced when the bare foot contacted a vinyl sheet coated with mineral oil. Lower extremity kinematics were acquired using a video-based motion capture system. Fourteen and 12 subjects could be unambiguously categorized as having fallen or recovered, respectively. Four variables demonstrated significant between-group differences and two were used to compute the probability of the slip outcome using logistic regression. The variables were the displacement of the foot during the slip and the angle of the shank relative to the ground at the instant of ground contact just prior to the slip. Separate univariate logistic regressions using each variable were significant and correctly classified about 70% of the slip outcomes. The results demonstrated that previously published values for the displacement and velocity of the slipping foot, 10cm and 50cm/s, respectively, may not accurately represent the upper limits beyond which recovery is not possible. The results also demonstrated that heel-strike angle, reflective of stride length, exerts a significant influence on the outcome of a slip.
本研究的目的是在健康受试者中诱发滑倒，以此来确定在滑倒脚的位移和速度分别超过普遍接受的10厘米和50厘米/秒的限度的情况下，从诱发滑倒中恢复是否可能，并确定是否存在与步态相关的变量使个体在滑倒后易摔倒。33名年轻的赤脚成年人，在配备仪器的安全带保护下，在进行了一系列无干扰步行试验后接受了单次滑倒试验。当赤脚接触涂有矿物油的乙烯基片时诱发滑倒。使用基于视频的运动捕捉系统获取下肢运动学数据。分别有14名和12名受试者可明确归类为摔倒或恢复。四个变量显示出显著的组间差异，其中两个变量用于通过逻辑回归计算滑倒结果的概率。这些变量是滑倒过程中脚的位移以及滑倒前地面接触瞬间小腿相对于地面的角度。使用每个变量进行的单独单变量逻辑回归具有显著性，并且正确分类了约70%的滑倒结果。结果表明，先前公布的滑倒脚的位移和速度值（分别为10厘米和50厘米/秒）可能无法准确代表无法恢复的上限。结果还表明，反映步长的脚跟撞击角度对滑倒结果有显著影响。
