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，以获得预防老年人严重福尔斯的信息。用高速摄像机拍摄了25名老年男性和12名青年男性跨越三种不同高度障碍物的过程，并进行了生物力学分析。主要结果如下：1.随着障碍物高度的增加，两组的步行速度均呈下降趋势，但两组的净空高度变化不明显; 2.随着障碍物高度的增加，两组的肢体屈曲度均呈增加趋势，尤其是前腿的髋（股）部。老年人右脚高障碍落地后上臂摆动消失，躯干前倾迅速增加; 3.青年人跨越高障碍时支撑腿垂直地面反力模式有两个峰值，但下降幅度较大。老年人的GRF有两种类型，一种与青年人相似，另一种没有大倾角。4.在足趾越障间隙附近，髋关节的伸展力矩占主导地位。随着障碍物高度的增加，两组的负伸展扭矩功率在间隙和负屈曲扭矩功率前的脚着陆前的领先腿的髋关节的增加。支撑腿的扭矩和功率模式与正常行走相似。髋关节的机械功在年轻人中明显大于老年人。由于经常出现从行走过程中的旅行扰动中恢复的降低策略，因此建议髋关节肌肉组织的重要性，以防止老年人严重的福尔斯。

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.