Biomechanical study on falls in the elderly during walking : biomechanics of stepping over obstacles of different heights

本研究的目的是分析老年人和年轻人在跨越障碍物时的动作，并获得预防老年人严重跌倒的信息。采用高速摄像机对25名老年男性和12名年轻男性跨越3种不同高度障碍物的过程进行录像，并用生物力学方法进行分析。主要研究结果总结如下：随着障碍物高度的增加，行走速度降低，但两组的间隙高度变化不显著。随着障碍高度的增加，两组的肢体屈曲，特别是领先腿的臀部（大腿）增加。老年人右脚落地高障碍物后，上臂摆动消失，躯干前倾迅速增加。跨高障碍物时，支撑腿垂直地面反力分布有两个峰值，且在青年期下降幅度较大。在老年人中发现了两种类型的GRF模式，即一种与年轻人相似，另一种没有出现大的下降。在脚趾的障碍间隙周围，髋关节的延伸扭矩占主导地位。随着障碍高度的增加，两组在间隙处的负伸展扭矩功率增加，在脚着地前的负弯曲扭矩功率增加。支撑腿的扭矩和动力模式与正常行走相似。年轻人髋部的机械功明显大于老年人。由于在步行过程中经常出现从绊倒不安中恢复的降低策略，因此建议髋关节肌肉组织的重要性，以防止老年人严重跌倒。

The purpose of this study was to analyze the motions of elderly and young people in stepping over obstacles and to obtain information to prevetn serious falls in the elderly. Twenty-five elderly and 12 young males stepping over obstacles of three different heights were videotaped with a high speed video camera and were analyzed with biomechanical methods. Major results were summarized as follows.1.With the increase in obstacle heights, walking velocity decreased, but significant change in clearance height was not found both groups.2.With the increase in obstacle heights, flexions of the limb, especially the hip (thigh) of the leading leg increased in both groups. In the elderly, swing of the upper arm disappeared and the forward lean of the trunk rapidly increased after the right foot landing at high obstacle.3.Pattern of vertical ground reaction force of the support leg had two peaks with larger dip in the young when stepping over high obstacle. Two types of GRF patterns were found in the elderly, i.e. one was similar to that of the young, and another did not show large dip.4.Around the obstacle clearance of the toe, extension torque of the hip was dominant. With the increase in obstacle height, for both groups there found increases in negative extension torque power at the clearance and negative flexion torque power before the foot landing for the hip of the leading leg. Torque and power patterns in the support leg were similar to those of normal walking. Mechanical work of the hip was significantly larger in the young than the elderly.Since lowering strategy for recovery from a trip pertubation during walking frequently appeared, the importance of the hip musculature was suggested to prevent serious falls in the elderly.