Department of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, Hong Kong, China.
Department of Prosthetics and Orthotics, Tuen Mun Hospital, Hong Kong, China.
Prosthet Orthot Int. 2023 Apr 1;47(2):168-171. doi: 10.1097/PXR.0000000000000202. Epub 2022 Nov 30.
Knee orthoses can potentially reduce muscular activities of the quadriceps. The aim of this study was to investigate the effect of a custom flexion-resist and extension-assist knee orthosis on electromyographic activities of quadriceps during lateral stepping (step-up and step-down). Flexion resistance and extension assistance mechanisms were set by a pair of linear springs built into the orthotic knee joints. Electromyography (EMG) signals were collected from rectus femoris (RF), vastus medialis obliquus (VMO), and vastus lateralis (VL) during lateral step-up and lateral step-down activities in 7 healthy young adults. Peak normalized root mean square (RMS) EMG signals of each muscle, as well as VMO:VL ratio, were compared between orthotic and nonorthotic conditions using the Wilcoxon signed-rank test. The knee orthosis significantly reduced the normalized RMS EMG signals of the RF and VL during lateral stepping ( p < 0.05). No significant difference was found in the VMO. The VMO:VL ratio significantly ( p < 0.05) increased under orthotic condition. The experiments demonstrated that the knee orthosis reduces the peak normalized RMS EMG signals of RF and VL, and alter the VMO:VL ratio of quadriceps in healthy young adults. Therefore, this study suggests that the flexion-resist and extension-assist knee orthosis may be effective in reducing muscular activities of RF and VL, which may alleviate patellofemoral loading. Future studies should delve into the effects of the knee orthosis in individuals with patellofemoral pain.
膝关节矫形器可能会降低股四头肌的肌肉活动。本研究旨在探讨定制的屈膝抵抗和伸膝助力膝关节矫形器对侧方跨步（上台阶和下台阶）时股四头肌肌电图活动的影响。矫形器膝关节内的一对线性弹簧设置了屈膝阻力和伸膝助力机构。在 7 名健康年轻成年人进行侧方上台阶和侧方下台阶活动时，从股直肌（RF）、股内侧斜肌（VMO）和股外侧肌（VL）中采集肌电图（EMG）信号。使用 Wilcoxon 符号秩检验比较矫形和非矫形条件下各肌肉的峰值归一化均方根（RMS）EMG 信号以及 VMO：VL 比值。膝关节矫形器显著降低了侧方跨步时 RF 和 VL 的归一化 RMS EMG 信号（p<0.05）。VMO 没有发现显著差异。VMO：VL 比值在矫形条件下显著增加（p<0.05）。实验表明，膝关节矫形器降低了 RF 和 VL 的峰值归一化 RMS EMG 信号，并改变了健康年轻成年人股四头肌的 VMO：VL 比值。因此，本研究表明，屈膝抵抗和伸膝助力膝关节矫形器可能有效降低 RF 和 VL 的肌肉活动，从而减轻髌股关节的负荷。未来的研究应该深入探讨膝关节矫形器对髌股疼痛患者的影响。
