Each year approximately one third of older adults fall and experience extensive musculoskeletal injuries and functional disabilities. An important element in maintaining dynamic balance is the regulation of whole-body angular momentum, which is achieved by proper foot placement with respect to the body center-of-mass as well as generation of appropriate ground reaction forces. Analyzing these quantities in younger and older adults may provide insight into differences in their underlying mechanics for maintaining dynamic balance. This study examined three-dimensional whole-body angular momentum in 13 healthy older (71.8 ± 8.3 years) and 9 younger (23.2 ± 2.8 years) adults walking at their self-selected and fastest-comfortable speeds. The older adults had a significantly higher range of frontal-plane angular momentum compared to the younger adults at both speeds, suggesting poorer mediolateral balance control. This difference was related to the older adults having a wider foot placement with respect to the body center-of-mass, which when combined with the vertical ground reaction force, created a higher destabilizing external moment during single-limb stance that acts to rotate the body towards the contralateral swing leg. To counteract this destabilizing moment, the older adults generated a higher hip abduction moment. There were no differences in the range of sagittal- and transverse-plane angular momentum between age groups at either speed. These results suggest that control of dynamic balance in the frontal-plane is more challenging than in the sagittal-plane for older adults and highlight the importance of proper weight transfer mechanisms and hip abductor force production for maintaining mediolateral balance during walking.

每年约有三分之一的老年人跌倒并遭受广泛的肌肉骨骼损伤和功能障碍。保持动态平衡的一个重要因素是全身角动量的调节，这是通过相对于身体重心适当放置脚以及产生适当的地面反作用力来实现的。分析年轻人和老年人的这些数量可以深入了解他们维持动态平衡的基本机制的差异。这项研究检查了 13 名健康的老年人（71.8 ± 8.3 岁）和 9 名年轻的（23.2 ± 2.8 岁）成年人以他们自己选择的最舒适的速度行走的三维全身角动量。与年轻人相比，老年人在两种速度下的额平面角动量范围都显着更高，这表明中外侧平衡控制较差。这种差异与老年人脚部相对于身体重心的位置更宽有关，当与垂直地面反作用力相结合时，在单肢站立时会产生更高的不稳定外部力矩，从而使身体旋转身体朝向对侧摆动腿。为了抵消这种不稳定的时刻，老年人产生了更高的髋关节外展时刻。在任一速度下，年龄组之间的矢状面和横向平面角动量范围没有差异。