ORIGINAL RESEARCH article
Front. Physiol.
Sec. Skeletal Physiology
Comparison of quadriceps femoris properties, surface electromyography parameters and foot posture asymmetries between patients with unilateral and bilateral knee osteoarthritis
Provisionally accepted
- 1Fifth Clinical School of Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China
- 2Guangdong Second Traditional Chinese Medicine Hospital, Guangzhou, China
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Objective: To investigate the differences in quadriceps femoris (QF) properties, surface electromyography (sEMG) parameters and foot posture asymmetries between patients with unilateral and bilateral knee osteoarthritis, and to analyze the factors related to foot posture asymmetry. Methods: A total of 32 patients with unilateral KOA (unilateral group, UG) and 35 patients with bilateral KOA (bilateral group, BG) were enrolled in this study. The severity of knee osteoarthritis symptoms was assessed, and the affected legs were categorized as relatively severe leg (RSL) or relatively moderate leg (RML) based on the Visual Analogue Scale (VAS). Surface electromyography (sEMG) was utilized to measure the root mean square (RMS) values of rectus femoris (RF), vastus medialis (VM), and vastus lateralis (VL) during a straight leg raise task. Biomechanical characteristics, including muscle tone and stiffness, were measured using MyotonPRO. The foot posture index-6 (FPI-6) was applied to assess foot posture and asymmetrical foot posture scores. Additionally, we calculated the asymmetry indices of muscle tone (AsyTone), stiffness (AsyStiffness), and root mean square (AsyRMS) for the QF, along with their FPI asymmetry scores. Result: In the evaluation of RF, VM, and VL in both groups, the RMS on the RML was significantly higher than that on the RSL (P < 0.05), while muscle tone and stiffness on the RSL were significantly higher than those of the RML (P < 0.05). In UG, AsyTone (RF), AsyTone (VM) , AsyStiffness (RF), AsyStiffness (VM), AsyStiffness (VL) and AsyRMS (VM) were significantly higher than those in BG (P < 0.05). There was no significant difference in AsyRMS (RF) and AsyRMS (VL) between the two groups (P > 0.05). Detailed research results are presented in the manuscript section. Conclusion: Both unilateral and bilateral patients with KOA exhibited a propensity for asymmetry in the properties of the QF, RMS values, and foot postures on both sides. Notably, unilateral patients tended to demonstrate this asymmetry more prominently and exhibit a higher prevalence of foot posture asymmetry compared to those bilateral patients. Furthermore, the degree of foot posture asymmetry was closely linked to pain severity and K/L grading whether in unilateral or bilateral KOA patients.
Keywords: knee osteoarthritis, quadriceps femoris, surface electromyography, Biomechanics, FPI-6, Foot posture, asymmetry
Received: 22 Sep 2025; Accepted: 17 Nov 2025.
Copyright: © 2025 Shen, Tian, Chen, Zhang, Cheng, Xiang and Xu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Xuemeng Xu, xuxuemeng@163.com
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.