{"title":"Phase-dependent loading characteristics of the supporting-side knee joint during the flying kick with a 180-degree inward turn in competitive Tai Chi.","authors":"Pan Deng, Mengyao Jia, Yong Ma","doi":"10.3389/fbioe.2026.1959458","DOIUrl":null,"url":null,"abstract":"<p><strong>Introduction: </strong>Competitive Tai Chi has increasingly incorporated high-difficulty aerial and single-leg landing techniques. The flying kick with a 180° inward turn (322C) is a demanding C-level movement that requires rapid take-off, aerial hand-foot slap, body rotation, and stable single-leg landing. However, the phase-dependent loading characteristics of the supporting-side knee joint during this movement remain unclear.</p><p><strong>Methods: </strong>Ten male competitive Tai Chi athletes performed the 322C while three-dimensional kinematics and ground reaction forces (GRF) were recorded. The movement was divided into four phases: take-off propulsion (P1), hand-foot slap (P2), flight end (P3), and landing cushioning (P4). Joint angles, moments, reaction forces, and vertical GRF (VGRF) were calculated using inverse dynamics. A subject-specific finite element (FE) model of the supporting-side knee was reconstructed from CT and MRI, and the peak landing loads were applied to evaluate internal tissue stresses.</p><p><strong>Results: </strong>P4 had the longest duration (1.639 s). VGRF reached 5.18 ± 1.84 body weight (BW), with a peak knee extension moment of 5.01 ± 1.64 N.m-kg<sup>-1</sup> and a peak compressive joint reaction force of 22.58 BW. FE analysis showed non-uniform stress distributions, with the highest von Mises stress observed in the anterior cruciate ligament (ACL; 54.24 MPa), posterior cruciate ligament (41.79 MPa), medial meniscus (23.53 MPa), and lateral femoral cartilage (9.62 MPa).</p><p><strong>Discussion: </strong>The 322C imposes different mechanical demands on the supporting-side knee across phases. P1 is mainly characterized by rapid knee extension and load transfer, whereas P4 involves high impact, axial compression, shear, and rotational stabilization. The stress concentrations observed in the ACL and anterior regions of the menisci indicate areas of relatively high local loading during the movement. These findings provide biomechanical information for understanding knee loading during the 322C and may help inform technique optimization and injury-prevention strategies in competitive Tai Chi.</p>","PeriodicalId":12444,"journal":{"name":"Frontiers in Bioengineering and Biotechnology","volume":"14 ","pages":"1959458"},"PeriodicalIF":5.8000,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13683722/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers in Bioengineering and Biotechnology","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.3389/fbioe.2026.1959458","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2026/1/1 0:00:00","PubModel":"eCollection","JCR":"Q1","JCRName":"BIOTECHNOLOGY & APPLIED MICROBIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Introduction: Competitive Tai Chi has increasingly incorporated high-difficulty aerial and single-leg landing techniques. The flying kick with a 180° inward turn (322C) is a demanding C-level movement that requires rapid take-off, aerial hand-foot slap, body rotation, and stable single-leg landing. However, the phase-dependent loading characteristics of the supporting-side knee joint during this movement remain unclear.
Methods: Ten male competitive Tai Chi athletes performed the 322C while three-dimensional kinematics and ground reaction forces (GRF) were recorded. The movement was divided into four phases: take-off propulsion (P1), hand-foot slap (P2), flight end (P3), and landing cushioning (P4). Joint angles, moments, reaction forces, and vertical GRF (VGRF) were calculated using inverse dynamics. A subject-specific finite element (FE) model of the supporting-side knee was reconstructed from CT and MRI, and the peak landing loads were applied to evaluate internal tissue stresses.
Results: P4 had the longest duration (1.639 s). VGRF reached 5.18 ± 1.84 body weight (BW), with a peak knee extension moment of 5.01 ± 1.64 N.m-kg-1 and a peak compressive joint reaction force of 22.58 BW. FE analysis showed non-uniform stress distributions, with the highest von Mises stress observed in the anterior cruciate ligament (ACL; 54.24 MPa), posterior cruciate ligament (41.79 MPa), medial meniscus (23.53 MPa), and lateral femoral cartilage (9.62 MPa).
Discussion: The 322C imposes different mechanical demands on the supporting-side knee across phases. P1 is mainly characterized by rapid knee extension and load transfer, whereas P4 involves high impact, axial compression, shear, and rotational stabilization. The stress concentrations observed in the ACL and anterior regions of the menisci indicate areas of relatively high local loading during the movement. These findings provide biomechanical information for understanding knee loading during the 322C and may help inform technique optimization and injury-prevention strategies in competitive Tai Chi.
期刊介绍：
The translation of new discoveries in medicine to clinical routine has never been easy. During the second half of the last century, thanks to the progress in chemistry, biochemistry and pharmacology, we have seen the development and the application of a large number of drugs and devices aimed at the treatment of symptoms, blocking unwanted pathways and, in the case of infectious diseases, fighting the micro-organisms responsible. However, we are facing, today, a dramatic change in the therapeutic approach to pathologies and diseases. Indeed, the challenge of the present and the next decade is to fully restore the physiological status of the diseased organism and to completely regenerate tissue and organs when they are so seriously affected that treatments cannot be limited to the repression of symptoms or to the repair of damage. This is being made possible thanks to the major developments made in basic cell and molecular biology, including stem cell science, growth factor delivery, gene isolation and transfection, the advances in bioengineering and nanotechnology, including development of new biomaterials, biofabrication technologies and use of bioreactors, and the big improvements in diagnostic tools and imaging of cells, tissues and organs.
In today`s world, an enhancement of communication between multidisciplinary experts, together with the promotion of joint projects and close collaborations among scientists, engineers, industry people, regulatory agencies and physicians are absolute requirements for the success of any attempt to develop and clinically apply a new biological therapy or an innovative device involving the collective use of biomaterials, cells and/or bioactive molecules. “Frontiers in Bioengineering and Biotechnology” aspires to be a forum for all people involved in the process by bridging the gap too often existing between a discovery in the basic sciences and its clinical application.
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