Department of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, 999077, Hong Kong Special Administrative Region.
Department of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, 999077, Hong Kong Special Administrative Region; Research Institute for Sports Science and Technology, The Hong Kong Polytechnic University, 999077, Hong Kong Special Administrative Region.
Gait Posture. 2023 Mar;101:145-153. doi: 10.1016/j.gaitpost.2023.02.010. Epub 2023 Feb 15.
Lower extremity muscle fatigue affects gait stability and increases the probability of injuries in the elderly.
How does prolonged walking-induced fatigue affect lower limb muscle activity, plantar pressure distribution, and tripping risk?
Eighteen elderly adults walked fast on a treadmill for 60 minutes at a fixed speed. The plantar pressure was measured with an in-shoe monitoring system, eight lower limb muscles were monitored using surface electromyography, and foot movements were tracked by a motion capture analysis system. The above data and participants' subjective fatigue level feedback were collected every 5 minutes. Statistical analysis used the Friedman one-way repeated measures analysis of variance by ranks test followed by Wilcoxon signed-ranks test with Benjamini-Hochberg stepwise correction.
The subjective reported fatigue on the Borg scale increased gradually from 1 to 6 (p = 0.001) during the 60 minutes, while the EMG amplitude of vastus medialis significant decreased (p = 0.013). The results of plantar pressure demonstrated that the distribution of load and impulse shifted medially in both the heel and arch regions while shifted laterally in both the toes and metatarsal regions. The significantly increased contact area supports this shift at the medial arch (p = 0.036, increased by 6.94%, the 60 minute vs. the baseline). The symmetry of medial-lateral plantar force increased at the toes, metatarsal, and arch regions. The significantly increased parameters also include the swing time and contact time. The minimum foot clearance was reduced, increasing tripping probability, not significantly, though.
This study facilitates a better understanding of changes in lower limb muscle activity and gait parameters during prolonged fast walking. Besides, this study has good guiding significance for developing smart devices based on plantar force, inertial measurement units, and EMG sensors to monitor changes in muscle activation in real-time and prevent tripping.
下肢肌肉疲劳会影响步态稳定性，增加老年人受伤的概率。
长时间行走引起的疲劳如何影响下肢肌肉活动、足底压力分布和绊倒风险？
18 名老年人在跑步机上以固定速度快速行走 60 分钟。使用鞋内监测系统测量足底压力，使用表面肌电图监测 8 块下肢肌肉，使用运动捕捉分析系统跟踪脚部运动。每隔 5 分钟收集上述数据和参与者的主观疲劳程度反馈。使用 Friedman 单向重复测量方差分析秩检验，然后进行 Wilcoxon 符号秩检验和 Benjamini-Hochberg 逐步校正。
在 60 分钟内，Borg 量表上的主观疲劳感逐渐从 1 级增加到 6 级（p = 0.001），而股直肌的 EMG 振幅显著降低（p = 0.013）。足底压力的结果表明，在脚跟和足弓区域，负荷和冲量的分布向内侧转移，而在脚趾和跖骨区域则向外侧转移。显著增加的接触面积支持内侧足弓的这种转移（p = 0.036，增加了 6.94%，60 分钟与基线相比）。脚趾、跖骨和足弓区域的内侧-外侧足底力对称性增加。参数的显著增加还包括摆动时间和接触时间。虽然最小的足离地间隙减小，增加了绊倒的可能性，但并不显著。
本研究有助于更好地理解长时间快速行走过程中下肢肌肉活动和步态参数的变化。此外，本研究对开发基于足底力、惯性测量单元和肌电图传感器的智能设备具有良好的指导意义，可实时监测肌肉激活的变化，防止绊倒。
