Journal of biomechanics最新文献_第5页

Let’s dance −Postural control in ballroom dance Couples: Differences between Profesfsional and amateur dancers 交际舞舞伴的姿势控制：专业舞者与业余舞者的差异。

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-01-01 DOI: 10.1016/j.jbiomech.2025.113140

Justyna Michalska, Żaneta Szuplak, Kajetan J. Słomka, Grzegorz Juras

Assessing ballroom dancers as a pair rather than as isolated subjects provides a deeper insight into postural control mechanisms. The aim of this study was to evaluate postural sway in ballroom dancers by comparing the male partner, the female partner, and the dance couple in the standard dance position. Seven international standard ballroom dance couples and fourteen amateur dancers with three months of ballroom training participated voluntarily. Postural sway was assessed using two force plates. Subjects assumed a standard dance position preceded by a short dance phase and were instructed to hold the position for 30 s. Each trial was repeated twice. Center of pressure (COP) parameters were calculated for the anterior–posterior and medio–lateral planes, and a two-way mixed-design ANOVA was applied to assess group and positional effects Significant main effects of group (professional vs. amateur dancers) were found for COP parameters in both planes, with professionals showing higher range of COP (ra COP), root mean square of COP (rms COP), and velocity of COP (v COP) values (p ≤ 0.003, η²p = 0.20–0.50).The effect of condition (male, female, pair) was also significant for most COP variables (p ≤ 0.001, η²p = 0.15–0.41), with female dancers demonstrating lower v COP and Sample entropy (SampEn) values compared to males and pairs. No significant group × position interactions were observed in the anterior–posterior plane (p ≥ 0.06), whereas a significant interaction appeared in the medio–lateral plane for SampEn (p = 0.04, η²p = 0.15). Ballroom dance training influences postural sway. The female partner appears to stabilize the couple, while professional couples exhibit less regular COP signals, suggesting greater automation of postural control compared to amateurs.

将交际舞者作为一对而不是作为孤立的对象进行评估，可以更深入地了解姿势控制机制。本研究的目的是评估交际舞者的姿势摇摆，通过比较男性伴侣，女性伴侣和标准舞蹈姿势的舞蹈夫妇。7对国际标准交际舞组合和14名经过3个月交际舞培训的业余舞者自愿参加。用两个测力板评估体位摇摆。受试者在一个短暂的舞蹈阶段之前采取一个标准的舞蹈姿势，并被要求保持这个姿势30秒。每个试验重复两次。计算前后平面和中外侧平面的压力中心（COP）参数，并采用双向混合设计方差分析评估群体效应和位置效应。两个平面的COP参数均存在专业舞蹈演员和业余舞蹈演员的主效应，专业舞蹈演员的COP （ra COP）、COP均方根（rms COP）和COP速度（v COP）值的范围更高（p≤0.003,η2p = 0.20 ~ 0.50）。条件（男性、女性、伴侣）对大多数COP变量的影响也很显著（p≤0.001,η2p = 0.15-0.41），与男性和伴侣相比，女性舞者的v COP和样本熵（SampEn）值更低。SampEn前后平面无显著组位相互作用（p≥0.06），而中外侧平面有显著组位相互作用（p = 0.04, η2p = 0.15）。交际舞训练影响姿势摇摆。女性伴侣似乎稳定了夫妻关系，而职业伴侣则表现出较少的常规COP信号，这表明与业余伴侣相比，他们的姿势控制更自动化。

{"title":"Let’s dance −Postural control in ballroom dance Couples: Differences between Profesfsional and amateur dancers","authors":"Justyna Michalska, Żaneta Szuplak, Kajetan J. Słomka, Grzegorz Juras","doi":"10.1016/j.jbiomech.2025.113140","DOIUrl":"10.1016/j.jbiomech.2025.113140","url":null,"abstract":"<div><div>Assessing ballroom dancers as a pair rather than as isolated subjects provides a deeper insight into postural control mechanisms. The aim of this study was to evaluate postural sway in ballroom dancers by comparing the male partner, the female partner, and the dance couple in the standard dance position. Seven international standard ballroom dance couples and fourteen amateur dancers with three months of ballroom training participated voluntarily. Postural sway was assessed using two force plates. Subjects assumed a standard dance position preceded by a short dance phase and were instructed to hold the position for 30 s. Each trial was repeated twice. Center of pressure (COP) parameters were calculated for the anterior–posterior and medio–lateral planes, and a two-way mixed-design ANOVA was applied to assess group and positional effects Significant main effects of group (professional vs. amateur dancers) were found for COP parameters in both planes, with professionals showing higher range of COP (ra COP), root mean square of COP (rms COP), and velocity of COP (v COP) values (p ≤ 0.003, η<sup>2</sup>p = 0.20–0.50).The effect of condition (male, female, pair) was also significant for most COP variables (p ≤ 0.001, η<sup>2</sup>p = 0.15–0.41), with female dancers demonstrating lower v COP and Sample entropy (SampEn) values compared to males and pairs. No significant group × position interactions were observed in the anterior–posterior plane (p ≥ 0.06), whereas a significant interaction appeared in the medio–lateral plane for SampEn (p = 0.04, η<sup>2</sup>p = 0.15). Ballroom dance training influences postural sway. The female partner appears to stabilize the couple, while professional couples exhibit less regular COP signals, suggesting greater automation of postural control compared to amateurs.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"195 ","pages":"Article 113140"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145878320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Aberrant tissue mechanics and mechanotransduction during heart development in down syndrome 唐氏综合征心脏发育过程中的异常组织力学和机械转导。

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-01-01 DOI: 10.1016/j.jbiomech.2025.113103

Rachel S. Reeser , Mitchell C. VeDepo , Rukshika S. Hewawasam , Katherine A. Waugh , Kyndal A. Schade , Mostafa Abdel-Hafiz , Brisa Peña , Luisa Mestroni , Orfeo Sbaizero , Joaquin M. Espinosa , Chelsea M. Magin , Jeffrey G. Jacot

Individuals with Down syndrome (DS) account for 70% of all cases of patients diagnosed with a septal heart defect.

To investigate the mechanisms underlying aberrant septation in Down syndrome, we examined how altered extracellular-matrix composition and tissue stiffness in the Dp16 mouse model influence cardiomyocyte mechanotransduction using trisomy 21 iPSC-derived cardiomyocytes, revealing a potential biomechanical pathway contributing to congenital heart defects in the Down syndrome population.

We hypothesized that in DS, upregulation of type VI collagen and hyaluronic acid in the endocardial cushion increases cushion stiffness, altering cellular mechanotransduction and ultimately leading to differences in cell proliferation and gene expression that perturb heart development. Results found that endocardial cushions of the Dp16 mouse model of DS showed a non-significant trend toward increased stiffness compared to WT. Furthermore, iPSC-CM with trisomy 21 exhibited decreased proliferation following culture on substrates of increasing stiffness, and following cyclic mechanical stretch, DS iPSC-CM developed stress fibers, disorganized sarcomeres and a decreased expression of mature cardiac markers. Yet cyclic mechanical stretch of control iPSC-CM induced sarcomere alignment and increased mature cardiac gene expression compared to static conditions. These data argue that tissue mechanics, driven by upregulation of ECM proteins, lead to increased endocardial cushion stiffness in the Dp16 mouse, and that iPSC-CM with trisomy 21 aberrantly respond to changes to stiffness and stretch, ultimately proposing a novel avenue to investigate congenital heart defects in the DS population.

唐氏综合症（DS）患者占所有诊断为室间隔心脏缺陷患者的70%。为了研究唐氏综合征中异常分隔的机制，我们使用21三体ipsc衍生的心肌细胞，研究了Dp16小鼠模型中细胞外基质成分和组织刚度的改变如何影响心肌细胞的机械转导，揭示了唐氏综合征人群中导致先天性心脏缺陷的潜在生物力学途径。我们假设，在DS中，心内膜垫中VI型胶原蛋白和透明质酸的上调会增加垫的硬度，改变细胞的机械转导，最终导致细胞增殖和基因表达的差异，从而扰乱心脏发育。结果发现，与WT相比，Dp16小鼠DS模型的心内膜缓冲垫的刚度增加趋势不显著。此外，具有21三体的iPSC-CM在增加刚度的底物上培养后，增殖减少，并且在循环机械拉伸后，DS iPSC-CM出现应力纤维，紊乱的肌瘤和成熟心脏标志物的表达减少。然而，与静态条件相比，控制iPSC-CM的循环机械拉伸诱导肌节排列和增加成熟心脏基因表达。这些数据表明，由ECM蛋白上调驱动的组织力学导致Dp16小鼠心内膜垫刚度增加，并且iPSC-CM具有21三体，对刚度和拉伸的变化异常响应，最终为研究DS人群的先天性心脏缺陷提供了一种新的途径。

{"title":"Aberrant tissue mechanics and mechanotransduction during heart development in down syndrome","authors":"Rachel S. Reeser , Mitchell C. VeDepo , Rukshika S. Hewawasam , Katherine A. Waugh , Kyndal A. Schade , Mostafa Abdel-Hafiz , Brisa Peña , Luisa Mestroni , Orfeo Sbaizero , Joaquin M. Espinosa , Chelsea M. Magin , Jeffrey G. Jacot","doi":"10.1016/j.jbiomech.2025.113103","DOIUrl":"10.1016/j.jbiomech.2025.113103","url":null,"abstract":"<div><div>Individuals with Down syndrome (DS) account for 70% of all cases of patients diagnosed with a septal heart defect.</div><div>To investigate the mechanisms underlying aberrant septation in Down syndrome, we examined how altered extracellular-matrix composition and tissue stiffness in the Dp16 mouse model influence cardiomyocyte mechanotransduction using trisomy 21 iPSC-derived cardiomyocytes, revealing a potential biomechanical pathway contributing to congenital heart defects in the Down syndrome population.</div><div>We hypothesized that in DS, upregulation of type VI collagen and hyaluronic acid in the endocardial cushion increases cushion stiffness, altering cellular mechanotransduction and ultimately leading to differences in cell proliferation and gene expression that perturb heart development. Results found that endocardial cushions of the Dp16 mouse model of DS showed a non-significant trend toward increased stiffness compared to WT. Furthermore, iPSC-CM with trisomy 21 exhibited decreased proliferation following culture on substrates of increasing stiffness, and following cyclic mechanical stretch, DS iPSC-CM developed stress fibers, disorganized sarcomeres and a decreased expression of mature cardiac markers. Yet cyclic mechanical stretch of control iPSC-CM induced sarcomere alignment and increased mature cardiac gene expression compared to static conditions. These data argue that tissue mechanics, driven by upregulation of ECM proteins, lead to increased endocardial cushion stiffness in the Dp16 mouse, and that iPSC-CM with trisomy 21 aberrantly respond to changes to stiffness and stretch, ultimately proposing a novel avenue to investigate congenital heart defects in the DS population.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"195 ","pages":"Article 113103"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145863149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Transport and deposition of inhalable aerosol drug particles in the human respiratory tract: variations across lung zones and the impact of breath-holding 可吸入气溶胶药物颗粒在人呼吸道的运输和沉积：跨肺区变化和屏气的影响。

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-01-01 DOI: 10.1016/j.jbiomech.2025.113138

Li Mengtao , Wang Yawei , Niu Luoyan , Zhang Haoran , He Dongze , Xi Renhan , Liu Jialong , Fan Yubo

The transport and deposition of drug particles within patient’s respiratory systems played a vital role in determining the therapeutic effectiveness of inhalation therapy. This study focused on transport of inhalable particles to different lung lobes and the influences of breath-holding. An in vitro simulation system including a 3D printed respiratory tract, a respiratory pattern simulator and special-designed particle collectors was built for investigating transport of drug particles to different lung zones. A corresponding computational fluid dynamics (CFD) model was also constructed. A transport ratio, ω_T, and a deposition ratio, ω_D, were defined for comparatively studying particles delivered to different lung lobes and deposited to different locations in the respiratory tract. In vitro experimental results revealed significant higher ωT to the left lung (29.1 % ± 4.2 %) compared to the right one (22.1 ± 4.4 %) under normal breathing condition, while ωT to the left upper (14.4 % ± 3.1 %) and left lower lobes were greater (14.6 % ± 2.8 %) than to the right lower lobe (10.5 % ± 3.0 %) than to the right middle and upper lobes (5.7 % ± 1.2 % and 6 % ± 2.0 %, respectively), and these results were in consistent to numerical simulation results. The results also showed that breath-holding increased nasal deposition ω_D by 31–65 %, but had little effects on overall ω_T to different lung lobes. These findings highlighted the role of airway anatomy and airflow dynamics in particles delivery, offering insights for optimizing inhalation therapy by identifying key mechanisms of aerosol transport and deposition.

药物颗粒在患者呼吸系统内的转运和沉积对吸入治疗的疗效起着至关重要的作用。本研究的重点是可吸入颗粒在不同肺叶的转运和屏气的影响。构建了3D打印呼吸道、呼吸模式模拟器和专门设计的颗粒收集器的体外模拟系统，用于研究药物颗粒在不同肺区运输的情况。建立了相应的计算流体力学（CFD）模型。我们定义了转运比ωT和沉积比ωD，用于比较研究颗粒在不同肺叶的传递和在呼吸道不同位置的沉积。体外实验结果显示显著较高的ωT左肺(29.1%±4.2%)相比,正确的呼吸(22.1±4.4%)在正常条件下,虽然ωT左边上层(14.4%±3.1%)和左叶低(14.6%±2.8%)大于右叶(10.5%±3.0%)低于中间和右边上部叶(分别为5.7%±1.2%和6%±2.0%),和这些结果在数值模拟结果一致。结果还表明，屏气使鼻沉积ωD增加31- 65%，但对不同肺叶的总ωT影响不大。这些发现强调了气道解剖和气流动力学在颗粒输送中的作用，通过确定气溶胶运输和沉积的关键机制，为优化吸入治疗提供了见解。

{"title":"Transport and deposition of inhalable aerosol drug particles in the human respiratory tract: variations across lung zones and the impact of breath-holding","authors":"Li Mengtao , Wang Yawei , Niu Luoyan , Zhang Haoran , He Dongze , Xi Renhan , Liu Jialong , Fan Yubo","doi":"10.1016/j.jbiomech.2025.113138","DOIUrl":"10.1016/j.jbiomech.2025.113138","url":null,"abstract":"<div><div>The transport and deposition of drug particles within patient’s respiratory systems played a vital role in determining the therapeutic effectiveness of inhalation therapy. This study focused on transport of inhalable particles to different lung lobes and the influences of breath-holding. An in vitro simulation system including a 3D printed respiratory tract, a respiratory pattern simulator and special-designed particle collectors was built for investigating transport of drug particles to different lung zones. A corresponding computational fluid dynamics (CFD) model was also constructed. A transport ratio, <em>ω</em><sub>T</sub>, and a deposition ratio, <em>ω</em><sub>D</sub>, were defined for comparatively studying particles delivered to different lung lobes and deposited to different locations in the respiratory tract. In vitro experimental results revealed significant higher ωT to the left lung (29.1 % ± 4.2 %) compared to the right one (22.1 ± 4.4 %) under normal breathing condition, while ωT to the left upper (14.4 % ± 3.1 %) and left lower lobes were greater (14.6 % ± 2.8 %) than to the right lower lobe (10.5 % ± 3.0 %) than to the right middle and upper lobes (5.7 % ± 1.2 % and 6 % ± 2.0 %, respectively), and these results were in consistent to numerical simulation results. The results also showed that breath-holding increased nasal deposition <em>ω</em><sub>D</sub> by 31–65 %, but had little effects on overall <em>ω</em><sub>T</sub> to different lung lobes. These findings highlighted the role of airway anatomy and airflow dynamics in particles delivery, offering insights for optimizing inhalation therapy by identifying key mechanisms of aerosol transport and deposition.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"195 ","pages":"Article 113138"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145878342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Defining trunk kinematics associated with pregnant waddling gait 定义与孕妇蹒跚步态相关的躯干运动学

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-01-01 DOI: 10.1016/j.jbiomech.2025.113143

Zahra Abedzadehzavareh, Christopher P. Connolly, Lukas Krumpl, Robert D. Catena

A common gait pattern during pregnancy is waddling gait with increased step width, which is clinically identified by trunk sway, but the specific correlates to trunk sway remain understudied. Existing research has not kinematically validated the combination of movements as a unified waddling gait pattern. In this study we examined the relationships among trunk kinematic characteristics, step width, and balance control.

Twenty-three pregnant individuals were assessed every four weeks between 18 and 34 weeks of gestation. Participants completed a quiet standing balance test and treadmill walking, from which spatiotemporal variables and trunk kinematics were calculated. Multiple linear regressions assessed whether waddling gait characteristics correlate with balance and step width.

Over gestation, trunk kinematics showed no significant change. However, step width increased by nearly 1 cm through pregnancy (p = 0.044). Irrespective of pregnancy, wider step width was associated with less sagittal thorax motion with respect to global, but more thorax motion with respect to the pelvis. However, over the course of pregnancy, women who adopted more waddling gait had larger reductions in sagittal trunk motion with respect to global (R² = 0.255, p = 0.014).

This study is the first to identify how trunk characteristics correlate with waddling, but only trunk sagittal motion change was specific to pregnancy change in waddling. We identified pregnancy-related gait changes to guide prescribing supportive devices or exercises for balance, back, or pelvic pain. The findings may help healthcare providers be more mindful when deciding whether to restrict or encourage trunk motion in pregnant individuals.

妊娠期常见的步态模式是摇摇摆摆的步态，步宽增加，临床表现为躯干摆动，但与躯干摆动的具体相关性仍有待研究。现有的研究还没有从运动学上验证这些运动的组合是一种统一的蹒跚步态模式。在这项研究中，我们研究了躯干运动学特性、步宽和平衡控制之间的关系。23名孕妇在妊娠18至34周期间每4周接受一次评估。参与者完成了安静站立平衡测试和跑步机行走，从中计算时空变量和躯干运动学。多元线性回归评估摇摆步态特征是否与平衡和步宽相关。妊娠期间，躯干运动学无明显变化。然而，妊娠期台阶宽度增加了近1 cm （p = 0.044）。与妊娠无关，较宽的步宽与相对于整体矢状胸廓运动较少相关，但与相对于骨盆的胸廓运动较多相关。然而，在整个怀孕过程中，采用摇摇摆摆步态的女性相对于整体而言，躯干矢状面运动的减少幅度更大（R2 = 0.255, p = 0.014）。这项研究首次确定了躯干特征与蹒跚学步之间的关系，但只有躯干矢状运动的变化与蹒跚学步的妊娠变化有关。我们确定了妊娠相关的步态变化，以指导处方支持装置或平衡，背部或骨盆疼痛的锻炼。这一发现可能会帮助医疗服务提供者在决定是否限制或鼓励孕妇的躯干运动时更加谨慎。

{"title":"Defining trunk kinematics associated with pregnant waddling gait","authors":"Zahra Abedzadehzavareh, Christopher P. Connolly, Lukas Krumpl, Robert D. Catena","doi":"10.1016/j.jbiomech.2025.113143","DOIUrl":"10.1016/j.jbiomech.2025.113143","url":null,"abstract":"<div><div>A common gait pattern during pregnancy is waddling gait with increased step width, which is clinically identified by trunk sway, but the specific correlates to trunk sway remain understudied. Existing research has not kinematically validated the combination of movements as a unified waddling gait pattern. In this study we examined the relationships among trunk kinematic characteristics, step width, and balance control.</div><div>Twenty-three pregnant individuals were assessed every four weeks between 18 and 34 weeks of gestation. Participants completed a quiet standing balance test and treadmill walking, from which spatiotemporal variables and trunk kinematics were calculated. Multiple linear regressions assessed whether waddling gait characteristics correlate with balance and step width.</div><div>Over gestation, trunk kinematics showed no significant change. However, step width increased by nearly 1 cm through pregnancy (p = 0.044). Irrespective of pregnancy, wider step width was associated with less sagittal thorax motion with respect to global, but more thorax motion with respect to the pelvis. However, over the course of pregnancy, women who adopted more waddling gait had larger reductions in sagittal trunk motion with respect to global (R<sup>2</sup> = 0.255, p = 0.014).</div><div>This study is the first to identify how trunk characteristics correlate with waddling, but only trunk sagittal motion change was specific to pregnancy change in waddling. We identified pregnancy-related gait changes to guide prescribing supportive devices or exercises for balance, back, or pelvic pain. The findings may help healthcare providers be more mindful when deciding whether to restrict or encourage trunk motion in pregnant individuals.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"195 ","pages":"Article 113143"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Reliability of a new semi–automated algorithm to analyze vastus lateralis muscle architecture using extended field-of-view ultrasound 利用扩展视场超声分析股外侧肌结构的一种新的半自动算法的可靠性

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-01-01 DOI: 10.1016/j.jbiomech.2025.113145

Lucas Gidiel-Machado , Eduardo Rodrigues Lauz , Nathália Kolling da Rosa , Eliana Citolim Rech , Germano Buzatto de Souza , Victória dos Santos Turchetto , Lucas De Liz Alves , André Ivaniski-Mello , Heinrich Leon Souza Viera , Fábio Juner Lanferdini

Fascicle curvature is often disregarded in muscle architecture analyses, leading to errors in fascicle length (FL) and pennation angle (PA). This study aimed to examine the reliability of a semi-automated method for analyzing vastus lateralis (VL) muscle architecture from extended field–of–view (EFOV) ultrasound images, using a Python-based algorithm that accounts for fascicle curvature. This method was compared to manual linear analysis performed in ImageJ. Additionally, the influence of fascicle curvature versus linearity across different VL regions was investigated. EFOV ultrasound images of the VL muscle from 102 athletes were analyzed by three raters. Muscle thickness (MT) was assessed along the entire VL belly, while FL and PA were measured in the proximal, middle, and distal regions. Intraclass correlation coefficients (ICC) and Bland–Altman were used to evaluate reliability and agreement. ANOVA was used to assess fascicle curvature across VL regions. Each rater demonstrated good–to-excellent reliability between the Python algorithm and ImageJ. The raters mean inter-software reliability was excellent for FL (ICC = 0.97), PA (ICC = 0.95), and MT (ICC = 0.99). Bland–Altman analysis revealed minor discrepancies between software. In the curved versus linear fascicle analysis, the proximal region exhibited pronounced fascicle curvature and was the only region where FL and PA were significantly underestimated when assuming linearity. The semi-automated Python algorithm provides a reliable tool for analyzing VL muscle architecture from EFOV ultrasound images while accounting for fascicle curvature. Assuming fascicle linearity may lead to underestimation of FL and PA, particularly in the proximal VL region.

肌束曲率在肌肉结构分析中经常被忽略，导致肌束长度（FL）和笔划角（PA）的误差。本研究旨在通过扩展视场（EFOV）超声图像分析股外侧肌（VL）结构的半自动方法的可靠性，该方法使用基于python的算法，考虑筋束曲率。将该方法与在ImageJ中进行的手工线性分析进行比较。此外，研究了不同VL区域的束束曲率对线性度的影响。本文对102名运动员的上下颌肌的EFOV超声图像进行了分析。沿着整个VL腹部评估肌肉厚度（MT），而在近端，中部和远端测量FL和PA。使用类内相关系数（ICC）和Bland-Altman来评估信度和一致性。方差分析用于评估跨VL区域的神经束曲率。每个评分器都证明了Python算法和ImageJ之间的良好到出色的可靠性。评分者表示，FL （ICC = 0.97）、PA （ICC = 0.95）和MT （ICC = 0.99）的软件间信度优异。布兰德-奥特曼的分析揭示了软件之间的细微差异。在弯曲与线性的神经束分析中，近端区域表现出明显的神经束弯曲，并且是假设线性时FL和PA被显著低估的唯一区域。半自动Python算法为从EFOV超声图像中分析VL肌肉结构提供了可靠的工具，同时考虑了束束曲率。假设神经束线性可能会导致FL和PA的低估，特别是在近VL区域。

{"title":"Reliability of a new semi–automated algorithm to analyze vastus lateralis muscle architecture using extended field-of-view ultrasound","authors":"Lucas Gidiel-Machado , Eduardo Rodrigues Lauz , Nathália Kolling da Rosa , Eliana Citolim Rech , Germano Buzatto de Souza , Victória dos Santos Turchetto , Lucas De Liz Alves , André Ivaniski-Mello , Heinrich Leon Souza Viera , Fábio Juner Lanferdini","doi":"10.1016/j.jbiomech.2025.113145","DOIUrl":"10.1016/j.jbiomech.2025.113145","url":null,"abstract":"<div><div>Fascicle curvature is often disregarded in muscle architecture analyses, leading to errors in fascicle length (FL) and pennation angle (PA). This study aimed to examine the reliability of a semi-automated method for analyzing vastus lateralis (VL) muscle architecture from extended field–of–view (EFOV) ultrasound images, using a Python-based algorithm that accounts for fascicle curvature. This method was compared to manual linear analysis performed in ImageJ. Additionally, the influence of fascicle curvature <em>versus</em> linearity across different VL regions was investigated. EFOV ultrasound images of the VL muscle from 102 athletes were analyzed by three raters. Muscle thickness (MT) was assessed along the entire VL belly, while FL and PA were measured in the proximal, middle, and distal regions. Intraclass correlation coefficients (ICC) and Bland–Altman were used to evaluate reliability and agreement. ANOVA was used to assess fascicle curvature across VL regions. Each rater demonstrated good–to-excellent reliability between the Python algorithm and ImageJ. The raters mean inter-software reliability was excellent for FL (ICC = 0.97), PA (ICC = 0.95), and MT (ICC = 0.99). Bland–Altman analysis revealed minor discrepancies between software. In the curved <em>versus</em> linear fascicle analysis, the proximal region exhibited pronounced fascicle curvature and was the only region where FL and PA were significantly underestimated when assuming linearity. The semi-automated Python algorithm provides a reliable tool for analyzing VL muscle architecture from EFOV ultrasound images while accounting for fascicle curvature. Assuming fascicle linearity may lead to underestimation of FL and PA, particularly in the proximal VL region.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"195 ","pages":"Article 113145"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mechanical energetics of different sagittal gait patterns in children with bilateral spastic cerebral palsy 双侧痉挛性脑瘫患儿不同矢状面步态模式的机械能量学。

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-01-01 DOI: 10.1016/j.jbiomech.2025.113142

Kosar Barati, Farzam Farahmand, Saeed Behzadipour

Children with cerebral palsy (CP) often exhibit inefficient gait; however, the relationship between their distinct sagittal gait patterns and this inefficiency remains unclear. This study examined the mechanical energy characteristics of gait in a large cohort of children with bilateral spastic CP, classified into four sagittal gait patterns: Crouch, Apparent Equinus, Jump, and True Equinus. Three-dimensional gait data from 148 children with bilateral spastic CP and 19 typically developing (TD) controls were collected using motion capture. An extended inverted pendulum framework was applied to assess deviations of dimensionless kinetic, T, and potential, V, energy waveforms from optimal energy exchange during single support, in order to quantify the Amplitude and Phase Problems. Results indicated that the amplitude-related inefficiency was most pronounced in the Crouch pattern, characterized by elevated V amplitude without proportional increases in T, and least in True Equinus, which showed elevated amplitudes in both V and T; nevertheless, both patterns exhibited significantly higher amplitude ratios than TD (p < 0.05). All CP subgroups had positive time lags, compared with a slightly negative lag in TD, and reduced continuous relative phase values (p < 0.05), indicating impaired phase coordination. These inefficiencies resulted in significantly greater total energy fluctuations, cost of transport, and energy recovery index across all CP subgroups (p < 0.05), with sustained energy injection in early stance and dissipation in late stance, particularly in Crouch and Jump patterns. These findings reveal gait-pattern-specific biomechanical inefficiencies in CP, offering a quantitative foundation for targeted interventions to improve gait efficiency.

脑瘫（CP）患儿常表现为步态不佳；然而，它们独特的矢状步态模式与这种低效率之间的关系尚不清楚。本研究检测了一大群双侧痉挛性脑瘫患儿步态的机械能特征，将其分为四种矢状步态模式：蹲姿、表观马姿、跳跃和真马姿。采用动作捕捉技术收集了148例双侧痉挛性CP患儿和19例正常发育（TD）对照患儿的三维步态数据。采用一个扩展的倒立摆框架来评估在单支撑过程中无量纲的动能、T和势能、V能量波形与最优能量交换的偏差，以量化振幅和相位问题。结果表明，在克劳奇模式中，振幅相关的低效率最为明显，其特征是V振幅升高，但T没有成比例增加；在真马模式中，振幅相关的低效率最少，其特征是V和T都有振幅升高；然而，两种模式的振幅比都明显高于TD (p)

{"title":"Mechanical energetics of different sagittal gait patterns in children with bilateral spastic cerebral palsy","authors":"Kosar Barati, Farzam Farahmand, Saeed Behzadipour","doi":"10.1016/j.jbiomech.2025.113142","DOIUrl":"10.1016/j.jbiomech.2025.113142","url":null,"abstract":"<div><div>Children with cerebral palsy (CP) often exhibit inefficient gait; however, the relationship between their distinct sagittal gait patterns and this inefficiency remains unclear. This study examined the mechanical energy characteristics of gait in a large cohort of children with bilateral spastic CP, classified into four sagittal gait patterns: Crouch, Apparent Equinus, Jump, and True Equinus. Three-dimensional gait data from 148 children with bilateral spastic CP and 19 typically developing (TD) controls were collected using motion capture. An extended inverted pendulum framework was applied to assess deviations of dimensionless kinetic, T, and potential, V, energy waveforms from optimal energy exchange during single support, in order to quantify the Amplitude and Phase Problems. Results indicated that the amplitude-related inefficiency was most pronounced in the Crouch pattern, characterized by elevated V amplitude without proportional increases in T, and least in True Equinus, which showed elevated amplitudes in both V and T; nevertheless, both patterns exhibited significantly higher amplitude ratios than TD (p < 0.05). All CP subgroups had positive time lags, compared with a slightly negative lag in TD, and reduced continuous relative phase values (p < 0.05), indicating impaired phase coordination. These inefficiencies resulted in significantly greater total energy fluctuations, cost of transport, and energy recovery index across all CP subgroups (p < 0.05), with sustained energy injection in early stance and dissipation in late stance, particularly in Crouch and Jump patterns. These findings reveal gait-pattern-specific biomechanical inefficiencies in CP, offering a quantitative foundation for targeted interventions to improve gait efficiency.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"195 ","pages":"Article 113142"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145878317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Computer-supported spinal fusion rod shaping yields improved conformity compared to freehand bending 与徒手弯曲相比，计算机支持的脊柱融合棒成形提高了一致性

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2026-01-01 DOI: 10.1016/j.jbiomech.2025.113144

Tobias Götschi , Gian Maranta , Alexander Crotta , Frédéric Cornaz , Mazda Farshad , Jonas Widmer

During spinal fusion surgery, metallic rods must be shaped to conform to pedicle screw positions. Poor conformity can overload screws, causing pull-out or loosening. Manual freehand rod bending is perception-dependent, time-consuming, cognitively demanding, and variable. We propose and evaluate a workflow in which rod shape is computed virtually via multi-objective optimization and then manually realized with a custom tool. The algorithm minimizes bend number and angle to improve efficiency and preserve rod strength.

Seven spine surgeons each bent rods for a 7-level screw configuration using both freehand and computer-supported methods in randomized order. Screw poses were reproduced in a custom test rig with uniaxial load cells to measure anteroposterior forces during seating and after fixation. Bending time, peak and residual forces, and re-bends were recorded.

Compared with freehand bending, computer-supported bending reduced median peak and residual forces by 41.9 % (p = 0.043) and 28.5 % (p = 0.027), respectively, and reduced bending and fixation time non-significantly by 27.4 % (p = 0.077). No re-bends or screw pull-outs occurred in the computer-supported group, whereas the freehand group required a median of 2.5 re-bends per trial.

Computer-supported rod bending produced mechanically favorable constructs while eliminating re-bending. The observed force reductions align with previous benchtop studies, consistent with improved rod–screw conformity and reduced screw–bone loading. This workflow may offer a practical compromise between the precision of automated shaping systems and the flexibility of manual intraoperative bending, with potential to improve consistency in multi-level spinal fusion procedures. Effects on operative time and clinical outcomes remain to be established.

在脊柱融合手术中，金属棒的形状必须符合椎弓根螺钉的位置。一致性差会使螺丝过载，导致拔出或松动。手动徒手杆弯曲是感知依赖，耗时，认知要求，和可变。我们提出并评估了一种工作流程，其中棒材形状通过多目标优化虚拟计算，然后使用自定义工具手动实现。该算法最大限度地减少弯曲次数和角度，以提高效率并保持杆的强度。7名脊柱外科医生按照随机顺序分别使用徒手和计算机支持的方法弯曲7节位螺钉。螺钉姿势在定制的单轴称重传感器测试台上重现，以测量坐位期间和固定后的前后力。记录弯曲时间、峰值和残余力以及再弯曲。与徒手弯曲相比，计算机辅助弯曲使中位峰值和残余力分别降低41.9% （p = 0.043）和28.5% (p = 0.027)，弯曲和固定时间减少27.4% （p = 0.077）。计算机辅助组没有再弯曲或螺钉拔出的情况发生，而徒手组每次试验需要2.5次再弯曲。计算机支持的杆弯曲产生了机械上有利的结构，同时消除了再次弯曲。观察到的力降低与之前的台式研究一致，与杆-螺钉一致性的改善和螺钉-骨载荷的降低相一致。该工作流程可以在自动成形系统的精度和人工术中弯曲的灵活性之间提供一个实用的折衷方案，有可能提高多层次脊柱融合手术的一致性。对手术时间和临床结果的影响仍有待确定。

{"title":"Computer-supported spinal fusion rod shaping yields improved conformity compared to freehand bending","authors":"Tobias Götschi , Gian Maranta , Alexander Crotta , Frédéric Cornaz , Mazda Farshad , Jonas Widmer","doi":"10.1016/j.jbiomech.2025.113144","DOIUrl":"10.1016/j.jbiomech.2025.113144","url":null,"abstract":"<div><div>During spinal fusion surgery, metallic rods must be shaped to conform to pedicle screw positions. Poor conformity can overload screws, causing pull-out or loosening. Manual freehand rod bending is perception-dependent, time-consuming, cognitively demanding, and variable. We propose and evaluate a workflow in which rod shape is computed virtually via multi-objective optimization and then manually realized with a custom tool. The algorithm minimizes bend number and angle to improve efficiency and preserve rod strength.</div><div>Seven spine surgeons each bent rods for a 7-level screw configuration using both freehand and computer-supported methods in randomized order. Screw poses were reproduced in a custom test rig with uniaxial load cells to measure anteroposterior forces during seating and after fixation. Bending time, peak and residual forces, and re-bends were recorded.</div><div>Compared with freehand bending, computer-supported bending reduced median peak and residual forces by 41.9 % (p = 0.043) and 28.5 % (p = 0.027), respectively, and reduced bending and fixation time non-significantly by 27.4 % (p = 0.077). No re-bends or screw pull-outs occurred in the computer-supported group, whereas the freehand group required a median of 2.5 re-bends per trial.</div><div>Computer-supported rod bending produced mechanically favorable constructs while eliminating re-bending. The observed force reductions align with previous benchtop studies, consistent with improved rod–screw conformity and reduced screw–bone loading. This workflow may offer a practical compromise between the precision of automated shaping systems and the flexibility of manual intraoperative bending, with potential to improve consistency in multi-level spinal fusion procedures. Effects on operative time and clinical outcomes remain to be established.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"195 ","pages":"Article 113144"},"PeriodicalIF":2.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of body weight support on motor control in typically developing children and children with cerebral palsy 体重支持对正常发育儿童和脑瘫儿童运动控制的影响

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2025-12-27 DOI: 10.1016/j.jbiomech.2025.113139

Allyson K. Clarke , Andrew J. Ries , Michael H. Schwartz , Katherine M. Steele

Body weight support (BWS) is often provided during rehabilitation interventions or activities of daily living with assistive devices. For children with cerebral palsy (CP), interventions that provide support like BWS treadmill training, orthoses, or walkers have been shown to improve walking speed, endurance, and/or kinematics – although responses are variable and challenging to predict. How individuals alter their muscle activity and coordination in response to BWS provides insight into neuromuscular control and may inform the design of future interventions. The purpose of this study was to evaluate motor control while children with CP (n = 12) and typically developing (TD) peers (n = 8) walked on a treadmill with 1%, 20%, 40%, and 60% BWS. As BWS increased, activity of support muscles decreased for both CP and TD groups. Specifically, activity of the gluteus medius and gluteus maximus decreased by more than 35% for both groups at 60% BWS. The TD group also decreased soleus activity by 27% at 60% BWS, while the CP group decreased vastus lateralis activity by 26% at 60% BWS. Muscle synergy analysis was used to evaluate coordination. As expected, the children with CP had significantly reduced synergy complexity compared to TD peers (total variance accounted for by one synergy, tVAF₁ = 76.3 for CP versus 67.4 for TD averaged across all conditions). However, synergy complexity did not change with BWS for either group. These findings suggest that although BWS may assist mobility by reducing demand on support muscles, it does not directly modulate motor control.

体重支持（BWS）通常在康复干预或使用辅助设备进行日常生活活动期间提供。对于患有脑瘫（CP）的儿童，提供支持的干预措施，如BWS跑步机训练、矫形器或助行器，已被证明可以提高步行速度、耐力和/或运动学——尽管反应是可变的，难以预测。个体如何改变肌肉活动和协调以应对BWS提供了对神经肌肉控制的见解，并可能为未来干预措施的设计提供信息。本研究的目的是评估CP儿童（n = 12）和正常发育儿童（n = 8）在1%、20%、40%和60% BWS的跑步机上行走时的运动控制能力。随着BWS的增加，CP组和TD组的支持肌活性均下降。具体来说，在60% BWS时，两组的臀中肌和臀大肌的活动下降了35%以上。TD组在60% BWS时比目鱼肌活动降低27%，而CP组在60% BWS时股外侧肌活动降低26%。肌肉协同分析用于评价协调性。正如预期的那样，与TD同龄人相比，CP儿童的协同复杂性显著降低（一种协同作用的总方差，CP的tVAF1 = 76.3，而TD在所有条件下的平均tVAF1 = 67.4）。然而，两组的协同复杂性没有随着BWS的变化而变化。这些发现表明，虽然BWS可能通过减少对支撑肌肉的需求来帮助活动，但它并不直接调节运动控制。

{"title":"Influence of body weight support on motor control in typically developing children and children with cerebral palsy","authors":"Allyson K. Clarke , Andrew J. Ries , Michael H. Schwartz , Katherine M. Steele","doi":"10.1016/j.jbiomech.2025.113139","DOIUrl":"10.1016/j.jbiomech.2025.113139","url":null,"abstract":"<div><div>Body weight support (BWS) is often provided during rehabilitation interventions or activities of daily living with assistive devices. For children with cerebral palsy (CP), interventions that provide support like BWS treadmill training, orthoses, or walkers have been shown to improve walking speed, endurance, and/or kinematics – although responses are variable and challenging to predict. How individuals alter their muscle activity and coordination in response to BWS provides insight into neuromuscular control and may inform the design of future interventions. The purpose of this study was to evaluate motor control while children with CP (n = 12) and typically developing (TD) peers (n = 8) walked on a treadmill with 1%, 20%, 40%, and 60% BWS. As BWS increased, activity of support muscles decreased for both CP and TD groups. Specifically, activity of the gluteus medius and gluteus maximus decreased by more than 35% for both groups at 60% BWS. The TD group also decreased soleus activity by 27% at 60% BWS, while the CP group decreased vastus lateralis activity by 26% at 60% BWS. Muscle synergy analysis was used to evaluate coordination. As expected, the children with CP had significantly reduced synergy complexity compared to TD peers (total variance accounted for by one synergy, tVAF<sub>1</sub> = 76.3 for CP versus 67.4for TD averaged across all conditions). However, synergy complexity did not change with BWS for either group. These findings suggest that although BWS may assist mobility by reducing demand on support muscles, it does not directly modulate motor control.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"196 ","pages":"Article 113139"},"PeriodicalIF":2.4,"publicationDate":"2025-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145924212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparison of lengthening and shortening stiffness tests in single skeletal muscle fibres 单个骨骼肌纤维拉伸和缩短刚度试验的比较

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2025-12-26 DOI: 10.1016/j.jbiomech.2025.113141

Rachael Principato, K.Josh Briar, Stephen H.M. Brown

Studies of skeletal muscle fibre function often incorporate stiffness tests to provide information on contractile performance. These tests are most often performed by applying rapid small (<0.5 % fibre length) lengthening or shortening steps and measuring the corresponding change in force. Despite these stiffness tests being regularly performed in studies of contractile function, their repeatability during contractions has not been evaluated, and reported differences in stiffness measured from lengthening versus shortening tests have not been fully evaluated. Single muscle fibres were chemically permeabilized and maximally activated at three different lengths. During maximal activation at each length three lengthening and three shortening tests were performed; these were then repeated with the fibre relaxed. Both stiffness and force measures were normalized to fibre size (stiffness normalized to modulus and force normalized to stress (i.e. specific force)) to best represent the intrinsic properties of the fibres. Active modulus tests were highly repeatable with mean coefficient of variations (CoV) less than 0.028 (2.8 %). Active modulus was on average 28 % higher in all fibres in response to the lengthening compared to the shortening tests. Interestingly, correlations between specific force and active modulus were significantly (p < 0.01) higher for the shortening (r = 0.86) compared to lengthening (r = 0.78) tests. Relaxed modulus tests were less repeatable with mean CoVs ranging from 0.089 to 0.151 (8.9 to 15.1 %). Relaxed modulus was not significantly affected by the direction (lengthening versus shortening) of the test.

骨骼肌纤维功能的研究通常包括刚度测试，以提供有关收缩性能的信息。这些测试通常是通过施加快速的小的（纤维长度的<； 0.5%）延长或缩短步骤并测量相应的力变化来进行的。尽管这些刚度测试在收缩功能研究中经常进行，但它们在收缩过程中的可重复性尚未得到评估，并且从延长和缩短测试中测量的刚度差异尚未得到充分评估。单个肌肉纤维被化学渗透，并在三个不同的长度上被最大限度地激活。在每个长度的最大激活时进行了3次延长和3次缩短试验；然后在放松纤维的情况下重复这些动作。刚度和力测量都归一化为纤维尺寸（刚度归一化为模量，力归一化为应力（即比力）），以最好地代表纤维的内在特性。主动模量试验重复性高，平均变异系数（CoV）小于0.028（2.8%）。与缩短试验相比，所有纤维在加长后的活性模量平均高出28%。有趣的是，与延长测试（r = 0.78）相比，缩短测试（r = 0.86）的比力和主动模量之间的相关性显著（p < 0.01）更高。松弛模量试验的重复性较差，平均cov范围为0.089至0.151（8.9至15.1%）。松弛模量不受测试方向（延长或缩短）的显著影响。

{"title":"Comparison of lengthening and shortening stiffness tests in single skeletal muscle fibres","authors":"Rachael Principato, K.Josh Briar, Stephen H.M. Brown","doi":"10.1016/j.jbiomech.2025.113141","DOIUrl":"10.1016/j.jbiomech.2025.113141","url":null,"abstract":"<div><div>Studies of skeletal muscle fibre function often incorporate stiffness tests to provide information on contractile performance. These tests are most often performed by applying rapid small (<0.5 % fibre length) lengthening or shortening steps and measuring the corresponding change in force. Despite these stiffness tests being regularly performed in studies of contractile function, their repeatability during contractions has not been evaluated, and reported differences in stiffness measured from lengthening versus shortening tests have not been fully evaluated. Single muscle fibres were chemically permeabilized and maximally activated at three different lengths. During maximal activation at each length three lengthening and three shortening tests were performed; these were then repeated with the fibre relaxed. Both stiffness and force measures were normalized to fibre size (stiffness normalized to modulus and force normalized to stress (i.e. specific force)) to best represent the intrinsic properties of the fibres. Active modulus tests were highly repeatable with mean coefficient of variations (CoV) less than 0.028 (2.8 %). Active modulus was on average 28 % higher in all fibres in response to the lengthening compared to the shortening tests. Interestingly, correlations between specific force and active modulus were significantly (p < 0.01) higher for the shortening (r = 0.86) compared to lengthening (r = 0.78) tests. Relaxed modulus tests were less repeatable with mean CoVs ranging from 0.089 to 0.151 (8.9 to 15.1 %). Relaxed modulus was not significantly affected by the direction (lengthening versus shortening) of the test.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"196 ","pages":"Article 113141"},"PeriodicalIF":2.4,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145908670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evaluation of stent retriever behavior at deployment and retrieval during mechanical thrombectomy 机械取栓过程中支架置入器在部署和取出时的行为评价。

IF 2.4 3区医学 Q3 BIOPHYSICS

Journal of biomechanics

Pub Date : 2025-12-20 DOI: 10.1016/j.jbiomech.2025.113130

Demitria A. Poulos , Michael T. Froehler , Bryan C. Good

The impact of stent retriever (SR)-clot integration for mechanical thrombectomy has been highlighted by several studies. However, it has also been shown that SRs can stretch or collapse during thrombectomies in tortuous anatomies. Therefore, this study focused on the behavior of commercial SRs (Solitaire and EmboTrap) during deployment and retrieval. Benchtop experiments were performed to measure the degree of SR collapse in an arterial model of varying tortuosity, and a custom testing structure was developed to measure SR outward forces at deployment and changes in radial force density (RFD).

The degree of collapse was significantly influenced by the model’s tortuosity index (TI) and the number of curves the SR pushwire interacted with (p < 0.05); a slight collapse was present at deployment, while more pronounced collapse occurred during retrieval. Solitaire SRs experienced more significant collapse than EmboTrap SRs, which was most pronounced in the highest tortuosity segment (TI = 1.74) where the Solitaire and EmboTrap degrees of collapse were 67.8 % and 32.5 %, respectively. While longer SRs were shown to have greater collapse overall, their distal segments remained expanded. We hypothesize this behavior supports prior clinical studies highlighting the benefits of longer SRs; during retrieval the distal SR region applies force to the clot to assist in dislodgment. SR behavior was also reflected in RFD trends. SRs with the least collapse generated the greatest RFDs and decreased with higher tortuosity. Overall, an evaluation of SR behaviors indicated that both SR design and length will influence the degree of collapse and RFD in tortuous segments.

一些研究强调了支架回收器(SR)-血栓整合对机械取栓的影响。然而，也有研究表明，在弯曲解剖结构的血栓切除术中，SRs可以拉伸或塌陷。因此，本研究主要关注商用SRs （Solitaire和EmboTrap）在部署和回收过程中的行为。在不同弯曲度的动脉模型中，进行了台式实验来测量SR塌陷的程度，并开发了一个定制的测试结构来测量SR在展开时的向外力和径向力密度（RFD）的变化。模型的扭转指数（TI）和SR推丝与之相互作用的曲线数(p)显著影响模型的坍塌程度

{"title":"Evaluation of stent retriever behavior at deployment and retrieval during mechanical thrombectomy","authors":"Demitria A. Poulos , Michael T. Froehler , Bryan C. Good","doi":"10.1016/j.jbiomech.2025.113130","DOIUrl":"10.1016/j.jbiomech.2025.113130","url":null,"abstract":"<div><div>The impact of stent retriever (SR)-clot integration for mechanical thrombectomy has been highlighted by several studies. However, it has also been shown that SRs can stretch or collapse during thrombectomies in tortuous anatomies. Therefore, this study focused on the behavior of commercial SRs (Solitaire and EmboTrap) during deployment and retrieval. Benchtop experiments were performed to measure the degree of SR collapse in an arterial model of varying tortuosity, and a custom testing structure was developed to measure SR outward forces at deployment and changes in radial force density (RFD).</div><div>The degree of collapse was significantly influenced by the model’s tortuosity index (TI) and the number of curves the SR pushwire interacted with (p < 0.05); a slight collapse was present at deployment, while more pronounced collapse occurred during retrieval. Solitaire SRs experienced more significant collapse than EmboTrap SRs, which was most pronounced in the highest tortuosity segment (TI = 1.74) where the Solitaire and EmboTrap degrees of collapse were 67.8 % and 32.5 %, respectively. While longer SRs were shown to have greater collapse overall, their distal segments remained expanded. We hypothesize this behavior supports prior clinical studies highlighting the benefits of longer SRs; during retrieval the distal SR region applies force to the clot to assist in dislodgment. SR behavior was also reflected in RFD trends. SRs with the least collapse generated the greatest RFDs and decreased with higher tortuosity. Overall, an evaluation of SR behaviors indicated that both SR design and length will influence the degree of collapse and RFD in tortuous segments.</div></div>","PeriodicalId":15168,"journal":{"name":"Journal of biomechanics","volume":"195 ","pages":"Article 113130"},"PeriodicalIF":2.4,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145819378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0