Annals of Biomedical Engineering最新文献

{"title":"Analysis of the Effect of Anatomical Variability on Atrial Fibrillation Dynamics Through a Novel Framework for Personalised Atrial Model Generation.","authors":"Victor Gonçalves Marques, Ali Gharaviri, Simone Pezzuto, Eduard Guasch, Lluís Mont, Pietro Bonizzi, Stef Zeemering, Ulrich Schotten","doi":"10.1007/s10439-026-04265-9","DOIUrl":"https://doi.org/10.1007/s10439-026-04265-9","url":null,"abstract":"<p><strong>Purpose: </strong>Atrial fibrillation (AF) is both influenced by and contributes to atrial structural remodelling, including atrial enlargement and fibrosis. In this work, we aimed to understand how differences in atrial anatomy affect AF inducibility and dynamics, both without and with fibrosis, through in silico models.</p><p><strong>Methods: </strong>Atrial wall anatomies from late gadolinium-enhanced magnetic resonance imaging (LGE-MRI) were used to generate personalised models. Detailed intra- and inter-atrial structures (pectinate muscles, Bachmann's bundle, fossa ovalis, coronary sinus, and fibre orientations) were mapped onto patient-specific atrial anatomies through a novel strategy using universal atrial coordinates and a highly detailed reference model. Patient-specific endomysial fibrosis was incorporated based on LGE-MRI. We quantified AF and macro-reentrant atrial tachycardia (MRAT) initiation rates in models with and without fibrosis, comparing reentry dynamics using renewal theory.</p><p><strong>Results: </strong>We generated personalised models of 10 patients, all but one with low-fibrotic content (Utah stages ≤ 2). Anatomical variability did not significantly affect AF initiation rates in both non-fibrotic (54.0 ± 13.7%, p = 0.43) and fibrotic models (53.5 ± 15.3%, p = 0.37). For AF + MRAT, initiation rates varied significantly among fibrotic models (p = 0.04) but not among non-fibrotic ones (p = 0.14). Reentry formation rates varied significantly across anatomies both with and without fibrosis (p < 0.04). With fibrosis, reentry destruction rates also varied significantly (p < 0.02). The number of simultaneous reentries varied significantly across patient anatomies (p < 0.001 without fibrosis, p < 0.05 with fibrosis), with fibrosis altering reentry counts in 2 patients (p < 0.02).</p><p><strong>Conclusion: </strong>Atrial anatomy influenced patient-specific variability in AF reentry dynamics, while fibrosis played a limited modifying role in this low-fibrotic cohort.</p>","PeriodicalId":7986,"journal":{"name":"Annals of Biomedical Engineering","volume":" ","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148417839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical Stimulation in Bone-on-Chip Platforms: A Systematic Review of Osteogenic Responses in Medical and Dental Applications.","authors":"Astero Maria Theodosaki, Chrysa Tsiavaki, Foteini Machla, Ioannis Fragkioudakis, Dimitrios Tortopidis, Maria Kokoti, Athina Bakopoulou","doi":"10.1007/s10439-026-04246-y","DOIUrl":"10.1007/s10439-026-04246-y","url":null,"abstract":"<p><p>Bone healing, remodeling, and pathology are strongly regulated by mechanical stimulation. However, conventional two-dimensional (2D) in vitro culture systems fail to reproduce the complex mechanical and biological microenvironment of human bone, limiting their translational relevance. In recent years, bone-on-chip (BoC) platforms, as part of the broader organ-on-chip (OoC) technology, have emerged as advanced microfluidic systems that enable the study of bone biology under dynamic and highly controlled conditions that more closely mimic in vivo physiology. This systematic review aimed to gather the available in vitro evidence on mechanically stimulated BoC models, with a particular focus on osteogenic differentiation outcomes and the technical characteristics underlying these platforms. Following a comprehensive literature search and structured data extraction, biological parameters (cell types, culture conditions, scaffolds), chip design and fabrication strategies, mechanical loading modalities, and assessment assays were systematically analyzed. Across the included studies, fluid shear stress was the most frequently applied mechanical stimulus and was generally associated with enhanced osteogenic differentiation compared with static cultures, although substantial heterogeneity was observed in loading protocols and outcome measures. Overall, this review provides a consolidated technical and biological overview of mechanically stimulated BoC systems and highlights key methodological considerations for future platform development. By integrating microengineering approaches with bone and stem cell biology, BoC models hold significant potential for advancing bone tissue engineering, mechanobiology research, and translational applications, including dentistry-related bone regeneration and biomaterial testing.</p>","PeriodicalId":7986,"journal":{"name":"Annals of Biomedical Engineering","volume":" ","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148409858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The CathPilot: Usability and Feasibility Evaluation in Simulated-Use Endovascular Interventions.","authors":"Sina Mohammadmahdi Keshavarz, James Zhou, Alykhan Sewani, Sharon Cai, Graham Wright, Andrew Dueck, M Ali Tavallaei","doi":"10.1007/s10439-026-04255-x","DOIUrl":"https://doi.org/10.1007/s10439-026-04255-x","url":null,"abstract":"<p><p>Endovascular treatment of complex peripheral artery disease and chronic total occlusions remains a significant challenge. This is largely due to limited distal control of devices used and reliance on proximal manipulation with conventional catheters. To bridge this gap, we previously developed the CathPilot, a modular steerable catheter that integrates a self-expanding nitinol frame for local anchoring with a real-time graphical user interface that provides cross-sectional tip position feedback alongside fluoroscopy. This study compares the CathPilot with conventional non-steerable catheters in a simulated-use, within-subjects design. Eight interventional clinicians each performed three lesion-crossing attempts per device in a silicone phantom model of human vasculature. Silicone lesions were positioned in the left superficial femoral artery. Objective endpoints included lesion-crossing success, procedure time, fluoroscopy time, and radiation dose. Subjective assessments included the System Usability Scale (SUS) for perceived usability and NASA Task Load Index (NASA-TLX) for operator workload. Combining objective performance with human-factors instruments enabled a comprehensive assessment of the CathPilot's procedural usability against conventional catheters. CathPilot achieved a 92% lesion-crossing success rate with approximately 3 × improvement compared to conventional catheters. Clinician-level and lesion-level procedure times, and fluoroscopy times were significantly lower when using the CathPilot. Similarly, the NASA-TLX workload rating was significantly lower for CathPilot. Under simulated-use conditions, these findings indicate the potential of the CathPilot system to address endovascular revascularization challenges and demonstrate the added value of precise distal tip control, tracking, and support.</p>","PeriodicalId":7986,"journal":{"name":"Annals of Biomedical Engineering","volume":" ","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148417832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biomechanical Simulations Informed by Multimodal Measurements Link Symptoms to Glenohumeral Joint Forces Across Healthy and Pathological Rotator Cuffs.","authors":"Sarah M Barron, Joseph J King, Federico Pozzi, Jennifer A Nichols","doi":"10.1007/s10439-026-04276-6","DOIUrl":"10.1007/s10439-026-04276-6","url":null,"abstract":"<p><strong>Purpose: </strong>Rotator cuff tears pose a biomechanical challenge to glenohumeral joint stability and present with varied clinical symptoms. This study aimed to characterize glenohumeral joint contact force, a key indicator of mechanical stability, and its relationship to rotator cuff tear status and symptom severity.</p><p><strong>Methods: </strong>Twenty older adults, including six with full-thickness supraspinatus tears, performed eight tasks. Joint contact forces were estimated using a biomechanical shoulder model with four scapular degrees-of-freedom, driven by measured muscle activations and kinematics. Forces were characterized by compressive magnitude, direction, and path length to assess group differences and discriminate by tear status and symptom severity.</p><p><strong>Results: </strong>Participants with rotator cuff tears exhibited reduced compressive forces and more anteriorly situated joint contact forces than age-matched controls. The estimated force magnitudes were closer to instrumented implant data than prior modeling studies. Group differences were task-dependent and temporally dynamic; differences were largest at initiation and conclusion but converged during the task. Path lengths were significantly longer in the tear group. Compressive force magnitude provided the strongest classification for both tear status and symptom severity.</p><p><strong>Conclusion: </strong>This study advances understanding of the biomechanical consequences of rotator cuff tears, establishing a link between glenohumeral joint loading, structural pathology, and symptom severity. Joint force characteristics discriminated individuals by pathology and symptom severity, supporting their utility as objective markers of dysfunction. Our findings highlighted that mechanical consequences were most pronounced in the absence of passive restraint, implicating preparatory muscle activation and underscoring the importance of temporally resolved joint force characterizations in biomechanical assessments.</p>","PeriodicalId":7986,"journal":{"name":"Annals of Biomedical Engineering","volume":" ","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13494848/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148417841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neural Network-Driven Finite Element Modeling for Estimating Knee Joint Cartilage Mechanical Responses.","authors":"Mahan Nematollahi, Amir Esrafilian, Jere Lavikainen, Mika E Mononen, Lauri Stenroth, Jari Arokoski, David J Saxby, David G Lloyd, Rami K Korhonen","doi":"10.1007/s10439-026-04266-8","DOIUrl":"https://doi.org/10.1007/s10439-026-04266-8","url":null,"abstract":"<p><p>Low-fidelity, artificial intelligence (AI)-generated approaches are increasingly used to estimate kinematics and kinetics of human movement, which are traditionally measured by high-fidelity motion capture (Mocap) approaches. However, there are no methods to study knee joint tissue mechanics using such low-fidelity approaches. To do so, we investigated knee cartilage stresses and strains using finite element (FE) models driven by both high- and low-fidelity motion capture methods. We performed subject-specific FE modeling on nine healthy participants to evaluate tissue mechanical responses by two different approaches. High-fidelity kinematic and kinetic data were obtained through motion capture and musculoskeletal modeling, respectively, whereas artificial neural networks (ANNs) were used to estimate kinetic data from low-fidelity data (e.g., subject mass, height, age, gender, static knee abduction-adduction angle, and walking speed). These data were then used as loading inputs in the knee joint FE models that were generated from magnetic resonance images. The results indicated that the high- and low-fidelity approaches provided comparable estimates of maximum principal stress, maximum shear strain, and collagen fibril strain of tibial cartilage at the first peak of knee contact force (p > 0.05). Significant differences between the methods in the peak values of the analyzed parameters were observed at the second peak of knee contact force (p < 0.05), larger differences observed in the lateral joint compartment. However, most of these differences disappeared when comparing average values over the cartilage-cartilage contact areas. Our findings support the potential of the low-fidelity, AI-generated approach to assess tibial cartilage mechanics. This out-of-laboratory tool may enable cartilage failure prediction and improved management of osteoarthritis.</p>","PeriodicalId":7986,"journal":{"name":"Annals of Biomedical Engineering","volume":" ","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148417844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Airborne Ultrasound Surface Motion Camera: Application to Transfer Admittance Chest Imaging.","authors":"Frédéric Wintzenrieth, Mathieu Couade, Amèle Mouadil, Éric Saloux, Mathias Fink, Ros Kiri Ing, Sam Bayat","doi":"10.1007/s10439-026-04252-0","DOIUrl":"https://doi.org/10.1007/s10439-026-04252-0","url":null,"abstract":"<p><p>Lung mechanics are heterogeneous in virtually all respiratory diseases. Spatially mapping this heterogeneity without ionizing radiation and at bedside is not feasible with current techniques. Here, we use an Airborne Ultrasound Surface Motion Camera (AUSMC) to map the local transfer admittance of the respiratory system, in response to an oscillatory pressure source at the mouth. As a proof of concept, the local admittance maps are shown for two individuals: a COPD patient and an age-matched healthy subject. The system measures a far lower transfer admittance in the subject with COPD compared to the normal control. The consistency of this result is tested comparing interquartile ranges of the regional transfer admittance and impedance of 6 COPD patients vs 6 healthy subjects. Trial Registration Number: ClinicalTrials.gov NCT06661200. Registered on October 17^th 2024.</p>","PeriodicalId":7986,"journal":{"name":"Annals of Biomedical Engineering","volume":" ","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148403399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-Time Soft Tissue Deformation Framework for Haptic-Enabled Robotic Surgical Training in Virtual Reality.","authors":"Dhanya Menoth Mohan, Bijan Shirinzadeh, Yongmin Zhong, Julian Smith","doi":"10.1007/s10439-026-04264-w","DOIUrl":"https://doi.org/10.1007/s10439-026-04264-w","url":null,"abstract":"<p><strong>Purpose: </strong>Virtual reality-based robotic surgery training has received significant attention in recent years due to its numerous advantages, notably improved safety, an enhanced learning experience, and reduced cost. The visual realism and user immersiveness of such platforms are enhanced through the integration of appropriate soft tissue deformation models.</p><p><strong>Methods: </strong>This study presents a modified mass-spring-damper framework designed to provide stable, realistic soft tissue deformation while maintaining real-time performance, even for high-density mesh models. The proposed framework extends the conventional mass-spring model by introducing two kinds of spring-damper elements: deformation and restoring components. Optimization of the model parameters is performed through a combination of analytical derivation and empirical tuning. Various numerical simulation studies are performed to assess model restoring capability, numerical stability, and real-time performance.</p><p><strong>Results: </strong>The results show that the model produces physiologically realistic deformation responses, regains its initial shape characteristics when the external force is removed, and provides a stable response in real-time simulation. A high performance rate of 171.11 frames per second is achieved on high-density mesh models consisting of approximately 29,754 vertices. Moreover, the deformation solver consistently maintains an average update frequency of 2828.14 Hz, with a mean step time of 0.354 ms, demonstrating its real-time capability. Additional experiments involving synthetic tissue and a surgical end-effector validate the tissue response to external forces.</p><p><strong>Conclusion: </strong>The ability of the proposed framework to deliver real-time performance on high-density mesh models highlights its suitability for haptic-enabled robotic surgical training environments that demand both computational efficiency and visual realism.</p>","PeriodicalId":7986,"journal":{"name":"Annals of Biomedical Engineering","volume":" ","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148403565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational Modelling of Selective Capture Mechanisms in Conduction System Pacing.","authors":"Mohammadreza Kariman, Matthias A F Gsell, Edward J Vigmond, Aurel Neic, Christoph M Augustin, Gernot Plank","doi":"10.1007/s10439-026-04259-7","DOIUrl":"https://doi.org/10.1007/s10439-026-04259-7","url":null,"abstract":"<p><strong>Purpose: </strong>Conduction system pacing (CSP) is gaining clinical significance owing to its ability to restore a physiological activation sequence in the ventricles. Whilst His bundle pacing producing the most physiological activation is preferable, due to implant complications the selective activation of the left bundle branch (LBB) by LBB area pacing is considered an alternative, offering both a simpler implant and a physiological activation sequence. However, the physical mechanisms facilitating selective activation of the LBB remain poorly understood.</p><p><strong>Methods: </strong>We developed a structurally and biophysically detailed computer model of the interventricular septum and LBB to quantitatively elucidate the role of lead position, orientation and polarity in achieving optimal selective left bundle branch pacing (LBBP) thresholds, using a geometrically detailed model of a clinically widely used CSP lead.</p><p><strong>Results: </strong>A deep implant within the left ventricular subendocardium ensuring a direct contact between electrode and LBB is key for effective selective LBBP. For low strength, selective LBBP is feasible, but capturing the LBB in its entirety could only be achieved using higher strengths that led to non-selective LBBP. Switching the tip polarity to anodal was not beneficial, requiring higher strengths to activate the LBB. Lead orientation relative to the LBB bundles was found to influence the selective LBBP capture threshold and the number of synchronously activating bundles.</p><p><strong>Conclusion: </strong>The model explains the impedance trends that are clinically observed when advancing the tip through the interventricular septum into the LBB region, as well as sudden impedance drops associated with implant complications such as septal perforation or lead dislodgement. Quantitative consistency with clinically observed trends supports model credibility, and indicates that simulation may offer an effective approach for guiding the design of improved CSP leads, facilitating a selective and synchronous activation of the entire LBB.</p>","PeriodicalId":7986,"journal":{"name":"Annals of Biomedical Engineering","volume":" ","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148403469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Multimodal Strategy for Enhancing Minimally Invasive Ablation of Lung Tumor.","authors":"Rui Zhang, Kangwei Zhang, Yue Lou, Guangzhi Wang, Lisa X Xu","doi":"10.1007/s10439-026-04260-0","DOIUrl":"https://doi.org/10.1007/s10439-026-04260-0","url":null,"abstract":"<p><strong>Purpose: </strong>This study aimed to evaluate a novel multimodal thermal therapy (MTT)-defined here as sequential liquid nitrogen pre-freezing followed by radiofrequency ablation (RFA)-to overcome limitations of early lung tumor ablation by RFA-namely, high electrical impedance and heat sink effects, to achieve larger, more controllable ablation zones.</p><p><strong>Methods: </strong>Using a porcine lung model (n = 3 pigs, 6 ablations/pig), multimodal ablation (pre-freezing + RFA) was compared to conventional RFA. Protocols included: 1) test group 1: 8-min pre-freezing + 40 W/12-min RFA; 2) test group 2: 15-min pre-freezing + 40 W/15-min RFA; and 3) control group: 40 W/12-min RFA alone. Ablation zones were assessed via CT and histology (H&E). Real-time impedances and temperatures were monitored. A finite element model was developed to elucidate mechanisms.</p><p><strong>Results: </strong>In comparison with the same power input of conventional RFA, pre-freezing created a conductive \"parenchyma-like environment\" via gas-to-blood displacement, reducing initial impedance by 52% (from 167.7 ± 48.1 to 80.8 ± 10.6 Ω). Paired analysis confirmed that MTT significantly decreased impedance and increased ablation dimensions and total energy delivery (all p < 0.05). Parameters from the prediction model demonstrated spatial overlap between the pre-freezing 0 °C isotherm and the RFA 60 °C lethal boundary. Multimodal ablation increased the treatment zone minor diameter by 189% (25.7 ± 3.7 vs. 8.9 ± 1.6 mm). A longer treatment period further increased the diameter to 30 mm.</p><p><strong>Conclusion: </strong>Pre-freezing is a promising strategy to enhance pulmonary RFA efficiency, significantly enlarging ablation zones via reduced impedance and improved conductivity, while conformal boundaries of 0 °C/60 °C enable precise intraoperative control. This work addressed a key limitation in lung tumor ablation. Enabling single-probe creation of predictable, clinically relevant zones could improve local control for early-stage lung tumors, potentiating minimal invasive thermal ablation in clinical practice.</p>","PeriodicalId":7986,"journal":{"name":"Annals of Biomedical Engineering","volume":" ","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148403444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Simulated Body-Mass Reduction on Peak Knee Joint Loads During Daily Functional Activities.","authors":"Tianyang Fan, Tao Ma, Xinyu Fan, Qianze Helian, Ruoying Hao, Tao Sun","doi":"10.1007/s10439-026-04270-y","DOIUrl":"https://doi.org/10.1007/s10439-026-04270-y","url":null,"abstract":"<p><strong>Purpose: </strong>While weight management is a primary recommendation for individuals with or at risk of knee osteoarthritis (KOA), the isolated mechanical impact of body-mass reduction on knee joint loads remains incompletely understood. This study aimed to quantify the acute biomechanical responses of peak knee joint loads to simulated body-mass reduction across various daily functional activities.</p><p><strong>Methods: </strong>Eleven healthy adults performed level walking, stair ascent, stair descent, stand-to-sit, and sit-to-stand under a simulated overweight baseline and three unloading conditions created by progressively reducing externally added loads using weighted vests and limb straps. Motion data were recorded using a motion capture system, and OpenSim was used to estimate tibiofemoral contact force, patellofemoral contact force, and knee joint moment.</p><p><strong>Results: </strong>Simulated body-mass reduction generally reduced peak knee joint loads in a task-dependent manner. Peak tibiofemoral contact force decreased significantly across all tasks (p < 0.05), with pronounced reductions in high-flexion activities. Patellofemoral contact force and knee joint moment also decreased, although responses varied by task and variable. Furthermore, the magnitude of joint load reduction varied across the progressive stages of external unloading.</p><p><strong>Conclusion: </strong>The acute mechanical effects of simulated body-mass reduction on knee joint loads vary significantly across different functional tasks and joint compartments. These findings focus on the mechanical contribution of body-mass reduction to knee joint loading, providing quantitative biomechanical evidence to inform load-management strategies for individuals with excessive knee loading.</p>","PeriodicalId":7986,"journal":{"name":"Annals of Biomedical Engineering","volume":" ","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148395671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}