Department of Kinesiology and Physical Education, McGill University, 475 Pine Avenue West, H2W 1S4 Montreal, Canada.
Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, Cagliari, Italy.
Exp Gerontol. 2019 Sep;124:110656. doi: 10.1016/j.exger.2019.110656. Epub 2019 Jul 10.
Older age is associated with higher stride time variability in female and male gait, which may have a neuromuscular origin. We sought to determine how older age and sex affect muscle activation variability during gait, and how these patterns relate to stride time variability.
Ninety-three adults (51 females; aged 20-82 years) completed six gait trials at their self-selected speed. Cycle-to-cycle variabilities (CCVs) were calculated for stride time, and for amplitude of electromyography (EMG) of the rectus femoris (RF), tibialis anterior (TA), and gastrocnemius lateralis (GL) recorded over different gait phases. Statistical models tested for Age × Sex × Muscle effects and for relationships between EMG CCVs and stride time CCVs.
Significant Age and Age × Muscle effects on EMG CCV were observed in several phases of gait (p < .05), where each year of age was associated with 0.11-0.18% higher EMG CCV, generally in the RF. A significant Age × Sex × Muscle effect on EMG CCV at mid-stance (p < .05) indicated that, in females, each year of age was associated with 0.11% lower GL CCV. Significant but low strength correlations (ρ = 0.298-0.351) were found between EMG CCV and stride time CCV.
Associations between older age and higher muscle activation variability were generally sex-independent. A sex-dependency in GL activation variability may contribute to gait instability in aging females. Individual variabilities of muscle activation were not strongly related to stride time variability.
年龄较大与女性和男性步态中的步长时间变异性增加有关，这种变异性可能具有神经肌肉起源。我们试图确定年龄较大和性别如何影响步态中的肌肉激活变异性，以及这些模式如何与步长时间变异性相关。
93 名成年人（51 名女性；年龄 20-82 岁）以自定速度完成了六次步态试验。计算了步长时间的周期到周期变异性（CCV），以及股直肌（RF）、胫骨前肌（TA）和腓肠外侧肌（GL）的肌电图（EMG）振幅的 CCV，这些 EMG 是在不同的步态阶段记录的。统计模型测试了年龄×性别×肌肉的影响，以及 EMG CCV 和步长时间 CCV 之间的关系。
在几个步态阶段观察到年龄和年龄×肌肉对 EMG CCV 的显著影响（p<0.05），每增加一岁与 EMG CCV 增加 0.11-0.18%有关，通常在 RF 中。在中足支撑阶段观察到年龄×性别×肌肉对 EMG CCV 的显著影响（p<0.05），表明女性每增加一岁，GL 的 CCV 降低 0.11%。发现 EMG CCV 和步长时间 CCV 之间存在显著但强度较低的相关性（ρ=0.298-0.351）。
年龄较大与肌肉激活变异性增加之间的关联通常与性别无关。GL 激活变异性的性别依赖性可能导致老年女性步态不稳定。肌肉激活的个体变异性与步长时间变异性没有很强的相关性。
