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Finite element analysis of stress distributions in knee ligaments and menisci during the Taekwondo Roundhouse Kick
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  • Published: 13 March 2026

Finite element analysis of stress distributions in knee ligaments and menisci during the Taekwondo Roundhouse Kick

  • Mengyao Jia1,2,
  • Duo Li1,2,
  • Yong Ma1,2,
  • Lin Liu3,
  • Shijie Lin4,
  • Ruifeng Huang5,
  • Zhaoyi Wang1,2,
  • Weitao Zheng1,2 &
  • …
  • Xin Ji1,2 

Scientific Reports , Article number:  (2026) Cite this article

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We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.

Subjects

  • Anatomy
  • Engineering
  • Health care
  • Medical research

Abstract

To describe relative mechanical loading exposure and stress-distribution patterns in major knee ligaments and menisci during the Taekwondo Roundhouse kick at four biomechanically defined key moments (E1–E4). Twelve elite male Taekwondo athletes performed standardized Roundhouse kicks with synchronized motion capture and ground reaction force measurement. Cohort-mean kinematics and net knee joint reaction forces estimated in OpenSim were applied to a subject-specific knee finite element (FE) model. Four independent quasi-static FE snapshots were solved at E1–E4. Model contact behavior under a 1000 N axial compression benchmark was compared with published ranges for plausibility. Across E1–E4, the supporting leg showed consistently higher stress exposure in cruciate/collateral ligaments and menisci than the attacking leg. Stress hotspots were primarily localized near ligament attachment regions and at the posterior horn/peripheral zones of the menisci, with the supporting-leg lateral meniscus demonstrating the most pronounced meniscal stress concentration. The supporting knee bears the dominant mechanical demand during the Roundhouse kick, suggesting that training and technique optimization should prioritize load management of the supporting leg and control of stress exposure in key knee tissues.

Data availability

The raw data supporting the conclusion of this article will be made available by the authors, without undue reservation.

Abbreviations

ACL:

Anterior Cruciate Ligament

PCL:

Posterior Cruciate Ligament

MCL:

Medial Collateral Ligament

LCL:

Lateral Collateral Ligament

PL:

Patellar Ligament

MM:

Medial Meniscus

LM:

Lateral Meniscus

EMG:

Electromyography

GRF:

Ground Reaction Force

DOF:

Degrees of Freedom

6DOF:

Six Degrees of Freedom

FEA:

Finite Element Analysis

MRI:

Magnetic Resonance Imaging

CT:

Computed Tomography

DICOM:

Digital Imaging and Communications in Medicine

STL:

Stereolithography File Format

STEP:

Standard for the Exchange of Product Data

IOC:

International Olympic Committee

WTF:

World Taekwondo Federation (now World Taekwondo, WT)

BF:

Biceps Femoris (long head)

GMAX:

Gluteus Maximus

LG:

Lateral Gastrocnemius

MG:

Medial Gastrocnemius

SEM:

Semimembranosus

VL:

Vastus Lateralis

CI:

Confidence Interval

References

  1. Zhang, N. & Guan, J. M. Technical and tactical characteristics of Taekwondo men’s 58 kg champion Zhao Shuai at the 2016 Rio Olympics. Br. J. Sports Med. 46 (7), 485–491. https://doi.org/10.1136/bjsports-2012-091011 (2017).

    Google Scholar 

  2. Bridge, C. A., Ferreira da Silva Santos, J., Chaabene, H., Pieter, W. & Franchini, E. Physical and physiological profiles of taekwondo athletes. Sports Med. 44, 713–733. https://doi.org/10.1007/s40279-014-0159-9 (2014).

    Google Scholar 

  3. Zhang, N. & Guan, J. M. Technical and Tactical Characteristics of Taekwondo Men’s 58kg Champion Zhao Shuai in 2016 Rio Olympics. J. Beijing Sport Univ. 40 (2), 95–99. https://doi.org/10.19582/j.cnki.11-3785/g8.2017.02.015 (2017).

    Google Scholar 

  4. Mailapalli, D. R., Benton, J. & Woodward, T. W. Biomechanics of the taekwondo axe kick: a review. J. Hum. Sport Exerc. 10 (1), 141–149. https://doi.org/10.14198/jhse.2015.101.12 (2015).

    Google Scholar 

  5. Hao, Y., Duan, H. J. & Ji, Z. Q. Biomechanics research on the offensive back turning kick in long distance of elite Taekwondo players. J. Beijing Sport Univ. 34 (4), 64–67. https://doi.org/10.19582/j.cnki.11-3785/g8.2011.04.017 (2011).

    Google Scholar 

  6. Yan, H. W., Shan, W. & Gao, Z. H. Technique application characteristics of main rivals of Chinese women Taekwondo athletes in 49 kg class. J. Beijing Sport Univ. 38 (2), 112–116. https://doi.org/10.19582/j.cnki.11-3785/g8.2015.02.019 (2015).

    Google Scholar 

  7. Su, J. J. et al. Covariate analysis of kinematic characteristics of Taekwondo athletes’ ankle joints during turning kicks under different fatigue levels. Chin. J. Sports Med. 39 (12), 924–931. https://doi.org/10.16038/j.1000-6710.2020.12.002 (2020).

    Google Scholar 

  8. Xu, C. J., Liu, W. J., Liu, D. H. & Yu, H. L. Effect of hitting speed of four tactical movements of Taekwondo back roundhouse kick and its enlightenment for sports training. J. Chengdu Sport Univ. 46 (1), 114–120. https://doi.org/10.15942/j.jcsu.2020.01.018 (2020).

    Google Scholar 

  9. Son, B., Cho, Y. J., Jeong, H. S. & Lee, S. Y. Injuries in Korean elite taekwondo athletes: A prospective study. Int. J. Environ. Res. Public Health. 17 (14), 5143. https://doi.org/10.3390/ijerph17145143 (2020).

    Google Scholar 

  10. Altarriba-Bartes, A. et al. Epidemiology of injuries in elite taekwondo athletes: two Olympic periods cross-sectional retrospective study. BMJ open. 4 (2), e004605. https://doi.org/10.1136/bmjopen-2013-004605 (2014).

    Google Scholar 

  11. Son, M. et al. Postural stability for taekwondo athletes with repetitive ankle sprains during a single-leg stance. J. Phys. therapy Sci. 30 (3), 405–410. https://doi.org/10.1589/jpts.30.405 (2018).

    Google Scholar 

  12. Xu, D. et al. New insights optimize landing strategies to reduce lower limb injury risk. Cyborg Bionic Syst. 5, 0126. https://doi.org/10.34133/cbsystems.0126 (2024).

    Google Scholar 

  13. Xu, D. et al. Accurately and effectively predict the ACL force: Utilizing biomechanical landing pattern before and after-fatigue. Comput. Methods Programs Biomed. 241, 107761. https://doi.org/10.1016/j.cmpb.2023.107761 (2023).

    Google Scholar 

  14. Cristiani, R., van de Bunt, F., Kvist, J. & Stålman, A. High prevalence of meniscal ramp lesions in anterior cruciate ligament injuries. Knee Surg. Sports Traumatol. Arthrosc. 31 (1), 316–324. https://doi.org/10.1007/s00167-022-07135-8 (2023).

    Google Scholar 

  15. Kim, Y. J. et al. Posterior root tear of the medial meniscus in multiple knee ligament injuries. Knee 17 (5), 324–328. https://doi.org/10.1016/j.knee.2009.10.001 (2010).

    Google Scholar 

  16. Falco, C. et al. Influence of the distance in a roundhouse kick’s execution time and impact force in Taekwondo. J. Biomech. 42 (3), 242–248. https://doi.org/10.1016/j.jbiomech.2008.10.041 (2009).

    Google Scholar 

  17. Park, K. J. & Song, B. B. Injuries in female and male elite taekwondo athletes: a 10-year prospective, epidemiological study of 1466 injuries sustained during 250 000 training hours[J]. Br. J. Sports Med. 52 (11), 735–740. https://doi.org/10.1136/bjsports-2017-097530 (2018).

    Google Scholar 

  18. Zhu, L. & Gao, X. Clinical summary of conservative rehabilitation treatment for posterior cruciate ligament rupture in six Taekwondo athletes. Chin. J. Sports Med. (3), 2. https://doi.org/10.16038/j.1000-6710.2010.03.022 (2010).

  19. Ji, M. J. Analysis of injuries in taekwondo athletes[J]. J. Phys. Therapy Sci. 28 (1), 231–234. https://doi.org/10.1589/jpts.28.231 (2016).

    Google Scholar 

  20. Sun, Y., Liu, L. S. & Ma, Y. C. Finite element analysis of internal knee joint stresses under different side-cut angles and ground contact modes. Chin. J. Rehabilitation Med. 39 (10), 1449–1455. https://doi.org/10.3969/j.issn.1001-1242.2024.10.007 (2024).

    Google Scholar 

  21. Liu, L. S., Pan, Z. Y., Li, X. M. & Ma, Y. C. Analysis of knee joint stress characteristics under different touchdown methods during barefoot running. Chin. J. Rehabilitation Med. 40 (1), 53–60. https://doi.org/10.3969/j.issn.1001-1242.2025.01.009 (2025).

    Google Scholar 

  22. Gavagan, C. J. & Sayers, M. G. A biomechanical analysis of the roundhouse kicking technique of expert practitioners: A comparison between the martial arts disciplines of Muay Thai, Karate, and Taekwondo. PloS one. 12 (8), e0182645. https://doi.org/10.1371/journal.pone.0182645 (2017).

    Google Scholar 

  23. Liu, L. S., Pan, Z. Y., Li, X. M. & Ma, Y. C. Analysis of knee joint stress characteristics under different touchdown methods during barefoot running. J. Wuhan Sports Univ. 57 (1), 73–81. https://doi.org/10.15930/j.cnki.wtxb.2023.01.009 (2025).

    Google Scholar 

  24. Delp, S. L. et al. OpenSim: open-source software to create and analyze dynamic simulations of movement. IEEE Trans. Biomed. Eng. 54 (11), 1940–1950. https://doi.org/10.1109/TBME.2007.901024 (2007).

    Google Scholar 

  25. Alexander, N., Schwameder, H., Baker, R. & Trinler, U. Effect of different walking speeds on joint and muscle force estimation using AnyBody and OpenSim. Gait posture. 90, 197–203. https://doi.org/10.1016/j.gaitpost.2021.08.026 (2021).

    Google Scholar 

  26. Lu, Z., Li, X., Rong, M., Baker, J. S. & Gu, Y. Effect of rearfoot valgus on biomechanics during barbell squatting: A study based on OpenSim musculoskeletal modeling. Front. Neurorobotics. 16, 832005. https://doi.org/10.3389/fnbot.2022.832005 (2022).

    Google Scholar 

  27. Li, Y. L., Xu, Y., Chen, X. Y. & Ni, G. X. Effects of running fatigue on ankle biomechanics in runners with different levels of experience. Chin. J. Rehabilitation Med. 39 (11), 1714–1717. https://doi.org/10.3969/j.issn.1001-1242.2024.11.026 (2024).

    Google Scholar 

  28. Malige, A. et al. Biomechanical properties of common graft choices for anterior cruciate ligament reconstruction: a systematic review. Clin. Biomech. Elsevier Ltd. 95, 105636. https://doi.org/10.1016/j.clinbiomech.2022.105636 (2022).

    Google Scholar 

  29. Milinkovic, D. D. et al. Anatomic and biomechanical properties of flat medial patellofemoral ligament reconstruction using an adductor magnus tendon graft: a human cadaveric study. Am. J. Sports Med. 49 (7), 1827–1838. https://doi.org/10.1177/036354652110095 (2021).

    Google Scholar 

  30. Zhang, Y., Hao, Z. X., Jin, D. W. & Sun, M. X. A method of vivo human knee joint 3D model reconstruction based on MR images. Chin. Journal Rehabilitation Medicine. 22 (4), 339–342 (2007).

    Google Scholar 

  31. Bao, H. R. C., Zhu, D., Gong, H. & Gu, G. S. The effect of complete radial lateral meniscus posterior root tear on the knee contact mechanics: a finite element analysis. J. Orthop. Sci. 18, 256–263. https://doi.org/10.1007/s00776-012-0334-5 (2013).

    Google Scholar 

  32. Wang, J. Y. et al. The effects of different repair methods for a posterior root tear of the lateral meniscus on the biomechanics of the knee: a finite element analysis. J. Orthop. Surg, Res. 16 (1), 296. https://doi.org/10.1186/s13018-021-02435-0 (2021).

    Google Scholar 

  33. Shin, C. S., Chaudhari, A. M. & Andriacchi, T. P. Valgus plus internal rotation moments increase anterior cruciate ligament strain more than either alone. Med. Sci. Sports Exerc. 43 (8), 1484–1491. https://doi.org/10.1249/MSS.0B013E31820F8395 (2011).

    Google Scholar 

  34. Quatman, C. E. et al. Preferential loading of the ACL compared with the MCL during landing: a novel in sim approach yields the multiplanar mechanism of dynamic valgus during ACL injuries. Am. J. Sports Med. 42 (1), 177–186. https://doi.org/10.1177/0363546513506558 (2014).

    Google Scholar 

  35. Oh, Y. K., Lipps, D. B., Ashton-Miller, J. A. & Wojtys, E. M. What strains the anterior cruciate ligament during a pivot landing? Am. J. Sports Med. 40 (3), 574–583. https://doi.org/10.1177/0363546511432544 (2012).

    Google Scholar 

  36. Li, P. X. et al. Finite unicompartmental knee arthroplasty in ACL fracture of the knee joint. J. Med. Biomech. 35 (1), 70–76. https://doi.org/10.16156/j.1004-7220.2020.01.015 (2020).

    Google Scholar 

  37. Pan, Z. Y. et al. Finite element analysis on stress state of knee joint with different lateral cutting angles under expected conditions. J. Med. Biomech. 36 (5), 762–768. https://doi.org/10.16156/j.1004-7220.2021.05.016 (2021).

    Google Scholar 

  38. Alentorn-Geli, E. et al. Prevention of anterior cruciate ligament injuries in sports—Part I: Systematic review of risk factors in male athletes. Knee surgery, sports traumatology, arthroscopy, 22, 3–15. (2014). https://doi.org/10.1007/s00167-013-2725-3

  39. Dauty, M. et al. Anatomical and neuromuscular factors associated to non-contact anterior cruciate ligament injury. J. Clin. Med. 11 (5), 1402. https://doi.org/10.3390/jcm11051402 (2022).

    Google Scholar 

  40. Shin, C. S., Chaudhari, A. M. & Andriacchi, T. P. The influence of deceleration forces on ACL strain during single-leg landing: a simulation study. J. Biomech. 40 (5), 1145–1152. https://doi.org/10.1016/j.jbiomech.2006.05.004 (2007).

    Google Scholar 

  41. Floyd, E. R. et al. The natural history of medial meniscal root tears: a biomechanical and clinical case perspective. Front. Bioeng. Biotechnol. 9, 744065. https://doi.org/10.3389/fbioe.2021.744065 (2021).

    Google Scholar 

  42. Willinger, L., Lang, J. J., von Deimling, C., Diermeier, T., Petersen, W., Imhoff,A. B., … Achtnich, A. (2020). Varus alignment increases medial meniscus extrusion and peak contact pressure: a biomechanical study. Knee Surgery, Sports Traumatology, Arthroscopy, 28, 1092–1098. https://doi.org/10.1007/s00167-019-05701-1.

  43. Xiang, F. R. et al. Analysis of knee joint stress during drop jump landing in females with generalized joint hypermobility. J. Med. Biomech. 38 (2), 317–323. https://doi.org/10.16156/j.1004-7220.2023.02.017 (2023).

    Google Scholar 

  44. Jeon, S. W., Jung, M., Choi, C. H., Kim, S. G. & Kim, S. H. Factors related to meniscal extrusion and cartilage lesions in medial meniscus root tears. J. Knee Surg. 34 (02), 178–186. https://doi.org/10.1055/s-0039-1693708 (2021).

    Google Scholar 

  45. Elkin, J. L., Zamora, E. & Gallo, R. A. Combined anterior cruciate ligament and medial collateral ligament knee injuries: anatomy, diagnosis, management recommendations, and return to sport. Curr. Rev. Musculoskelet. Med. 12, 239–244. https://doi.org/10.1007/s12178-019-09549-3 (2019).

    Google Scholar 

  46. Wilson, W. T., Deakin, A. H., Payne, A. P., Picard, F. & Wearing, S. C. Comparative analysis of the structural properties of the collateral ligaments of the human knee. J. Orthop. sports Phys. therapy. 42 (4), 345–351. https://doi.org/10.2519/jospt.2012.3919 (2012). https://www.jospt.org/doi/

    Google Scholar 

  47. Ren, D. et al. The evaluation of the role of medial collateral ligament maintaining knee stability by a finite element analysis. J. Orthop. Surg, Res. 12, 1–10. https://doi.org/10.1186/s13018-017-0566-3 (2017).

    Google Scholar 

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Funding

The author(s) declared that financial support was received for the research, authorship, and/or publication of this article. This study was Joint supported by Hubei Provincial Natural Science Foundation and Sport Innovative Development of China (grant number 2025AFD652) and was supported by the East Lake Scholars Sponsorship Program of Wuhan Sports University in China (2023), Hubei Provincial Department of Education of China [grant number D20194101], the Hubei Provincial Department of Education Scientific Research Program for Young and Middle-aged Talents (grant number Q20224107), the Natural Science Basic Research Program of Shangxi Province [grant number 2022JQ-051], the Science and Technology Team Foundation of Wuhan Sports University [grant number 21KT02], and the 14th Five Year-Plan Advantageous and Characteristic Disciplines (Groups) of Colleges and Universities in Hubei Province [grant number 2021-05].

Author information

Authors and Affiliations

  1. School of Intelligent Sports Engineering, Wuhan Sports University, Wuhan, 430079, China

    Mengyao Jia, Duo Li, Yong Ma, Zhaoyi Wang, Weitao Zheng & Xin Ji

  2. Hubei Engineering Research Center for Intelligent Equipment in Sports and Health, Wuhan Sports University, Wuhan, 430079, China

    Mengyao Jia, Duo Li, Yong Ma, Zhaoyi Wang, Weitao Zheng & Xin Ji

  3. Dongguan University of Technology, Dongguan, 523808, Guangdong, China

    Lin Liu

  4. Northwest Polytechnical University, Xi’an, 710072, Shanxi, China

    Shijie Lin

  5. The Hong Kong Polytechnic University, Hong Kong, 999077, China

    Ruifeng Huang

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  1. Mengyao Jia
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Contributions

Mengyao Jia: Conceptualization, Data Management, Formal Analysis, Investigation, Methodology, Software, Supervision, Visualization, Writing - Original Draft, Writing - Review & Editing, Project Administration, Validation. Duo Li: Conceptualization, Methodology, Supervision, Writing - Review & Editing. Yong Ma: Funding Acquisition, Project Administration, Resources, Supervision, Writing - Review & Editing. Liu Lin: Investigation, Validation, Writing - Review & Editing. Lin Shijie: Funding Acquisition, Validation, Writing - Review & Editing. Huang Ruifeng: Data Management, Investigation, Validation, Writing - Review & Editing. Zhaoyi Wang: Investigation, Project Administration, Resources, Writing - Review & Editing. Zheng Weitao: Investigation, Data Management, Validation, Writing - Review & Editing. Xin Ji: Conceptualization, Methodology, Writing - Review & Editing.

Corresponding authors

Correspondence to Duo Li or Yong Ma.

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Competing interests

The authors declare no competing interests.

Ethics approval and consent to participate

This study was approved by the Ethics Committee of Wuhan Sports University (Approval No.: 2022048). All procedures complied with relevant institutional requirements and local legislation. Written informed consent was obtained from all participants prior to data collection. No personally identifiable information was collected; all data was anonymized and securely stored with access restricted to authorized research team members.

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Jia, M., Li, D., Ma, Y. et al. Finite element analysis of stress distributions in knee ligaments and menisci during the Taekwondo Roundhouse Kick. Sci Rep (2026). https://doi.org/10.1038/s41598-026-43031-8

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  • Received: 05 October 2025

  • Accepted: 28 February 2026

  • Published: 13 March 2026

  • DOI: https://doi.org/10.1038/s41598-026-43031-8

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Keywords

  • Finite element
  • Simulation
  • Biomechanics
  • Stress distribution
  • Knee joint
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