Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, 813 Ferst Dr. NW, Atlanta, GA, 30332, USA.
Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
Ann Biomed Eng. 2022 Jun;50(6):716-727. doi: 10.1007/s10439-022-02950-z. Epub 2022 Mar 27.
Tibiofemoral compression forces present during locomotion can result in high stress and risk damage to the knee. Powered assistance using a knee exoskeleton may reduce the knee load by reducing the work required by the muscles. However, the exact effect of assistance on the tibiofemoral force is unknown. The goal of this study was to investigate the effect of knee extension assistance during the early stance phase on the tibiofemoral force. Nine able-bodied adults walked on an inclined treadmill with a bilateral knee exoskeleton with assistance and with no assistance. Using an EMG-informed neuromusculoskeletal model, muscle forces were estimated, then utilized to estimate the tibiofemoral contact force. Results showed a 28% reduction in the knee moment, which resulted in approximately a 15% decrease in knee extensor muscle activation and a 20% reduction in subsequent muscle force, leading to a significant 10% reduction in peak and 9% reduction in average tibiofemoral contact force during the early stance phase (p < 0.05). The results indicate the tibiofemoral force is highly dependent on the knee kinetics and quadricep muscle activation due to their influence on knee extensor muscle forces, the primary contributor to the knee load.
在运动过程中，胫骨股骨压缩力可能导致膝关节承受高应力和损伤风险。使用膝关节外骨骼提供动力辅助可以减少肌肉所需的工作量，从而降低膝关节的负荷。然而，辅助对胫骨股骨力的确切影响尚不清楚。本研究旨在探讨早期站立阶段膝关节伸展辅助对胫骨股骨力的影响。九名健康成年人在带有双侧膝关节外骨骼的倾斜跑步机上行走，分别在有辅助和无辅助的情况下进行。使用肌电图启发的神经肌肉骨骼模型，估计肌肉力量，然后利用该模型估计胫骨股骨接触力。结果显示，膝关节力矩减少了 28%，这导致膝关节伸肌的激活减少了约 15%，随后的肌肉力量减少了 20%，导致早期站立阶段的峰值和平均胫骨股骨接触力分别显著减少了 10%和 9%（p<0.05）。结果表明，胫骨股骨力高度依赖于膝关节动力学和股四头肌的激活，因为它们影响膝关节伸肌的力量，而膝关节伸肌的力量是膝关节负荷的主要贡献者。
