Your new experience awaits. Try the new design now and help us make it even better

ORIGINAL RESEARCH article

Front. Public Health

Sec. Injury Prevention and Control

Biomechanical Analysis of Stair Walking Patterns and Their Implications for Knee Health in Young Males

Provisionally accepted
Yang  SunYang Sun1Qingkang  MeiQingkang Mei2Danyang  KouDanyang Kou1Jiujiang  LiuJiujiang Liu1Yi  YangYi Yang1Lian  DuanLian Duan1,3*Yuan  GaoYuan Gao1*
  • 1Yanshan University, Qinhuangdao, China
  • 2Hebei Mechanical and Electrical Vocational and Technical College, Xingtai, China
  • 3Beijing Sport University, Beijing, China

The final, formatted version of the article will be published soon.

Objective: Stair ambulation is an essential daily activity associated with maintaining mobility and musculoskeletal health, and its biomechanical characteristics may influence fall risk. This study aimed to examine how different stair-walking strategies—single-step and double-step ascent—affect peri-knee muscle forces and joint loading using OpenSim-based musculoskeletal simulations, thereby providing biomechanical insights for public health–oriented interventions in injury prevention and rehabilitation. Methods: Synchronized kinematic and kinetic data were imported into OpenSim musculoskeletal models to compute knee joint angles, joint reaction forces, and peri-knee muscle forces. The simulated muscle activation levels were then compared with synchronized surface electromyography (sEMG) signals to validate the reliability of the simulations. Results: Results indicated that the double-step stair ascent mode produced significantly greater step length (p =0.001) and larger peak hip (p =0.002) and knee (p =0.015) flexion compared with the single-step mode. Continuous-time SPM analysis further revealed that knee flexion remained significantly higher in the double-step mode throughout most of the single support phase (p <0.001), while no significant differences were observed in knee joint reaction forces (p >0.05). Muscle force analysis showed that quadriceps muscle force, including the quadriceps components (vastus medialis/lateralis/intermedius and rectus femoris) was significantly greater in the double-step mode during the early stage of the single support phase (p <0.001). For the hamstrings, only the biceps femoris long head demonstrated significant differences between modes (p <0.001), whereas the biceps femoris short head, semimembranosus, semitendinosus, and gastrocnemius showed no significant differences (p >0.05). Conclusion: Double-Step Mode increased step length, hip mobility, and quadriceps activation without significantly elevating knee joint forces, supporting knee stability under higher mechanical demands. From a public health perspective, stair walking may enhance lower-limb muscle engagement and potentially contribute to the maintenance of balance control and mobility, while Single-Step Mode may be safer for individuals with knee impairments by minimizing joint stress and supporting rehabilitation.

Keywords: Stair walking, KNEE BIOMECHANICS, Muscle force analysis, OpenSim simulation, Public health implications

Received: 14 Oct 2025; Accepted: 05 Nov 2025.

Copyright: © 2025 Sun, Mei, Kou, Liu, Yang, Duan and Gao. 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:
Lian Duan, dl1984@ysu.edu.cn
Yuan Gao, gaoyuan1107@ysu.edu.cn

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.