nils-herrmann/clean_scirepeval huggingface dataset:
Three-dimensional modelling of human quadriceps femoris forces.
Venue: Journal of biomechanics

Quadriceps intramuscular anatomy is typically described in two dimensions. However, anatomical descriptions indicate fascicles in the quadriceps may have a three-dimensional orientation. The purpose of this investigation was to quantify the maximum force generating capacity of the individual quadriceps' muscles in three dimensions. Muscle architectural parameters were obtained from three cadaver specimens (two female) and input into a geometry-based multiple fascicle muscle force model. Vastus lateralis, vastus medialis, and rectus femoris had partitions which could be defined based on differences in the sense and direction of fascicles between partitions. Vastus lateralis and rectus femoris were bipennate due to partitions sharing an aponeurosis. Vastus lateralis deep and superficial partitions exerted posterior- (maximum: -29 ± 5 N) and anterior-directed (maximum: 58 ± 15 N) forces on their shared distal aponeurosis. Rectus femoris medial and lateral partitions exerted medial- (maximum: -38 ± 17 N) and lateral-directed (maximum: 19 ± 12 N) forces on their shared proximal aponeurosis. All vastus medialis fascicles ran along the proximal-distal axis. However, fascicles arising near the lesser trochanter also ran along the superficial-deep axis, while fascicles arising from the linea aspera ran along the medial-lateral axis. Thus, vastus medialis could be divided into longus and oblique partitions. Due to the large pennation angle, vastus medialis oblique could exert maximum medial-directed (-219 ± 93 N) and proximal-directed (279 ± 168 N) forces at approximately -40° and -70° knee flexion, respectively, indicating dual roles for vastus medialis oblique dependent on knee flexion angle.
Raman spectroscopic determination of bone matrix quantity and quality augments prediction of human cortical bone mechanical properties.
Venue: Journal of biomechanics

Being independent contributors to bone mechanical resistance at the apparent level, quality and quantity of bone primary constituents are essential factors in better fracture risk assessment. Raman spectroscopy (RS) holds great potential for being a clinical tool with providing quality and quantity measurements of the bone mineralized matrix. Beyond mineral quality and quantity, recent years have revealed newly developed RS-derived bone compositional measurements focusing on organic matrix and water though their associations with bone mechanics have not been fully established yet. Herein, the author reported first thorough characterization study investigating associations between twenty different RS-derived measurements and mechanical properties of human cortical bone (i.e., yield and ultimate strength, elastic modulus, toughness, post-yield toughness, and post-yield strain). Forty-five rectangular human cortical beams harvested from all four anatomical quadrants of two male donors were tested under three-point bending. Raman spectra of each specimen were collected at the spectral range of 800 to 4000 cm-1. While correlations were tested among RS-derived measurements via Spearman's rank correlations, multivariate linear regression using mixed effects were used to determine the best RS-derived measurement or the combination of RS-derived measurements in predicting various mechanical properties of human cortical bone. Most of the RS-derived measurements were associated with the mechanical properties (Rm2 ranges from 8.9 to 68.3%, p < 0.05). The various linear combinations of six RS-derived measurements focusing on different aspects of bone matrix (i.e., ν1PO4/Amide I, ν1PO4/Amide III, Carbonate/ν1PO4, ~I1670/I1640, ~I3453/I2949, ~I3584/I2949) improved the prediction (Rm2 = 43.5 to 70.2%, p < 0.05). While a causal relationship still needs to be investigated, RS has a great potential to establish a robust patient-specific fracture risk prediction with the latest advances in technologies.
Aerodynamic investigation of tucked positions in alpine skiing.
Venue: Journal of biomechanics

The purpose of this investigation was to examine the aerodynamics of tucked positions in competitive alpine skiing. To further our understanding of how a skier's position affects the air flow and the resulting aerodynamic drag, a combination of both experimental and simulation methods was used. This study focused in particular on the effect of skier torso and thigh angles relative to the air flow direction, as these two angles have been previously found to be important determinants of aerodynamic performance in tucked positions. Two top 30 world-ranked skiers were investigated in two different wind tunnels, and the results were compared with Computational Fluid Dynamics (CFD) simulations performed using a 3D scan of one of the athlete. To quantify the effect of torso and thigh angles on skier drag, changes in drag were measured relative to baseline positions. Skier drag area increased by approximately 0.8 and 1.2% per degree increase in torso and thigh angles relative to the baseline position, respectively. This trend was consistent between both of the experimental wind tunnel tests as well as the CFD simulations, indicating good agreement between methods. The CFD simulations further indicated that the air flow about the lower legs made the largest contribution to skier drag, accounting for as much as 40-50% of the total drag area in low tuck positions. Based on these findings, a low tuck position where the torso angle approaches 0° and the knees help to fill the gap behind the armpits will minimize skier aerodynamic drag.
A comprehensive, open-source dataset of lower limb biomechanics in multiple conditions of stairs, ramps, and level-ground ambulation and transitions.
Venue: Journal of biomechanics

We introduce a novel dataset containing 3-dimensional biomechanical and wearable sensor data from 22 able-bodied adults for multiple locomotion modes (level-ground/treadmill walking, stair ascent/descent, and ramp ascent/descent) and multiple terrain conditions of each mode (walking speed, stair height, and ramp inclination). In this paper, we present the data collection methods, explain the structure of the open dataset, and report the sensor data along with the kinematic and kinetic profiles of joint biomechanics as a function of the gait phase. This dataset offers a comprehensive source of locomotion information for the same set of subjects to motivate applications in locomotion recognition, developments in robotic assistive devices, and improvement of biomimetic controllers that better adapt to terrain conditions. With such a dataset, models for these applications can be either subject-dependent or subject-independent, allowing greater flexibility for researchers to advance the field.
Walking lower extremity biomechanics of adolescents with autism spectrum disorder.
Venue: Journal of biomechanics

Although the literature indicates children with autism spectrum disorder (ASD) walk at slower speeds and altered kinematics compared to neurotypical controls, no research has examined walking at matched speeds. This study examined biomechanical differences between adolescents with ASD and matched (age, sex, and body mass index) neurotypical controls. Lower extremity biomechanics of seventeen adolescents with ASD and seventeen controls were compared at matched speeds: self-selected and a standardized 1.3 m/s. Controls exhibited greater eversion angles and hip abduction moments compared to those with ASD. This study found adolescents, which may have a more mature gait than young children, walk with a similar pattern in the propulsive plane (i.e. sagittal) as neurotypical controls, but with alterations in the supportive plane (i.e. frontal).
Relationship between the form and function of implant design in total knee replacement.
Venue: Journal of biomechanics

The implant design in total knee replacement affects postoperative functionality greatly, therefore, its optimization is of major concern. However, little is known about how implant design parameters affect active knee kinematics. Comprehensive in silico and in vitro sensitivity analyses were performed, based on one patient-specific, physical knee implant set and corresponding bone and knee implant surface geometry data. The implant surfaces were parametrized and varied systematically, resulting in 85 different knee implant surface models. In addition, four variations of extensor mechanism parameters, being the muscular attachment points defining the Q-Angle, were investigated. The variations were evaluated in a patient-specific multibody simulation model and an experimental testing rig and contributions of different implant designs and extensor mechanism parameters on kinematics were analysed. The results of the in silico and in vitro analyses showed good qualitative agreement. The highest deviations from the implant's reference kinematics were found for parameter variations of the femoral sagittal radii, the lateral trochlear elevation, the tibial sagittal slopes, the mediolateral position of the patellar ridge and the mediolateral position of the tuberositas tibiae. The implant design parameters identified with the highest functional relevance should be focused on in implant design. As the tuberositas tibiae's position constituted a main impact factor, it should also be considered during implant design and preoperative planning. Due to the competing influence of implant design parameters on active kinematics, respective parameters should be designed which are compatible to each other to avoid adverse constraints and associated functional limitations.
Flow topology and targeted drug delivery in cardiovascular disease.
Venue: Journal of biomechanics

Targeted drug delivery is a promising technique to direct the drug to the specific diseased region. Nanoparticles have provided an attractive approach for this purpose. In practice, the major focus of targeted delivery has been on targeting cell receptors. However, the complex fluid mechanics in diseased biomedical flows questions if a sufficient number of nanoparticles can reach the desired region. In this paper, we propose that hidden topological structures in cardiovascular flows identified with Lagrangian coherent structures (LCS) control drug transport and provide valuable information for optimizing targeted drug delivery efficiency. We couple image-based computational fluid dynamics (CFD) with continuum transport models to study nanoparticle transport in coronary artery disease. We simulate nanoparticle transport as well as the recently proposed shear targeted drug delivery system that couples micro-carriers with nanoparticle drugs. The role of the LCS formed near the stenosed artery in controlling drug transport is discussed. Our results motivate the design of smart micro-needles guided by flow topology, which could achieve optimal drug delivery efficiency.
Intranuclear strain in living cells subjected to substrate stretching: A combined experimental and computational study.
Venue: Journal of biomechanics

Nuclear deformation caused by mechanical stimuli has been suggested to significantly impact various cellular activities, such as gene expression, protein synthesis and mechanotransduction. To understand how nuclear deformation regulates cellular behaviors, the details of intranuclear strain distribution caused by mechanical stimuli as well as intranuclear mechanical properties are required. Here, we examine local mechanical strains within the nucleus in a living cell subjected to substrate stretching and estimate the local nuclear mechanical properties. A HeLa cell in a PDMS chamber was subjected to a 10% step-strain by using a custom-made uni-axial stretching device. Local displacements and the distribution of the equivalent strain within the nucleus were obtained from fluorescence images of the nucleus before and after the application of stretching. The intranuclear strain showed heterogeneous distribution, and higher strain regions were observed not only at the center, but also periphery of the nucleus. We examined the role of the chromatin condensation level and actin cytoskeleton by treating cells with Trichostatin A and Cytochalasin D, respectively. Interestingly, these treatments did not cause significant changes in the intranuclear strain distribution. Referring to the experimental results, we reproduced the nuclear strain distribution in a finite element model to estimate relative distribution of Young's modulus within the nucleus, and observed substantially lower Young's modulus levels in the peripheral regions of the nucleus relative to those found in the central regions of the nucleus. We reveal heterogeneous strain distribution within the nucleus in a living cell subjected to substrate stretching, and the results provide insights into the importance of heterogeneity of intranuclear mechanical properties.
Walking humans trade off different task goals to regulate lateral stepping.
Venue: Journal of biomechanics

People walk in complex environments where they must adapt their steps to maintain balance and satisfy changing task goals. How people do this is not well understood. We recently developed computational models of lateral stepping, based on Goal Equivalent Manifolds that serve as motor regulation templates, to identify how people regulate walking movements from step-to-step. In normal walking, healthy adults strongly maintain step width, but also lateral position on their path. Here, we used this framework to pose empirically-testable hypotheses about how humans might adapt their lateral stepping dynamics when asked to prioritize different stepping goals. Participants walked on a treadmill in a virtual-reality environment under 4 conditions: normal walking and, while given direct feedback at each step, walking while trying to maintain constant step width, constant absolute lateral position, or constant heading (direction). Time series of lateral stepping variables were extracted, and variability and statistical persistence (reflecting step-to-step regulation) quantified. Participants exhibited less variability of the prescribed stepping variable compared to normal walking during each feedback condition. Stepping regulation results supported our models' predictions: to maintain constant step width or position, people either maintained or increased regulation of the prescribed variable, but also decreased regulation of its complement. Thus, people regulated lateral foot placements in predictable and systematic ways determined by specific task goals. Humans regulate stepping movements to not only "just walk" (step without falling), but also to achieve specific goal-directed tasks within a specific environment. The framework and motor regulation templates presented here capture these important interactions.
Simulating finger-tip force using two common contact models: Hunt-Crossley and elastic foundation.
Venue: Journal of biomechanics

Musculoskeletal models of the hand rarely include fingerpad contact mechanics, thereby limiting our ability to simulate and examine hand-object interactions. The objective of this study was to evaluate whether two common contact models (Hunt-Crossley and Elastic Foundation) can accurately represent the fingerpad. Two musculoskeletal models of the index finger were created by adding fingerpad contact geometry using either the Hunt-Crossley or Elastic Foundation contact models. Key contact parameters (target force, contact area, and stiffness) were then systematically varied through 432 forward dynamic simulations to examine how these parameters influenced estimation of finger-tip forces. Across all simulations, variation in target force, contact area, and stiffness parameters impacted the computation time required to complete the simulations and the accuracy of the predicted finger-tip force. Computation time was over three times longer in simulations with high versus low values of contact area and stiffness in both contact models. For both contact models, larger contact area and stiffness values resulted in simulations that more closely predicted target force. However, across all simulations, the Hunt-Crossley model produced a greater proportion of accurate finger-tip force simulations than the Elastic Foundation model, suggesting that the Hunt-Crossley contact model may be preferable for modeling the fingerpad. Overall, our study demonstrates how the Hunt-Crossley and Elastic Foundation contact models behave in low-force biomechanical scenarios, such as those experienced during hand-object manipulation, and provides a foundation for incorporating contact mechanics into musculoskeletal models of the hand.
Microstructural and mechanical evaluations of region segmentation methods in classifications of osteonecrosis.
Venue: Journal of biomechanics

Measuring the location of necrotic lesions is necessary to diagnosis of osteonecrosis. Different region segmentation methods of the femoral head were proposed to quantitatively measure necrotic lesions including Japanese Investigation Committee for Avascular Necrosis (JIC) classification and China-Japan Friendship Hospital (CJFH) classification. Biomechanical methods could bring important information to evaluate the reasonability of these classifications. In this study, microstructural and mechanical properties of trabecular bone were quantitatively analyzed according to the region segmentation methods described in these classifications. Microstructural parameters of trabecular bone were analyzed based on micro-CT scanning. Mechanical properties were measured through Nanoindentation and micro-finite element analysis. It was found that microstructural and mechanical properties of trabecular bone in the middle region was more adaptive to load bearing than the medial and lateral regions according to the CJFH classification; lesions in the middle region could bring more changes to microstructure and stress distribution. According to JIC classification, differences of microstructural and mechanical properties among the three regions were not significant. Biomechanical characteristics of trabecular bones could be better distinguished with CJFH classification.
Patient-specific computational evaluation of stiffness distribution in ascending thoracic aortic aneurysm.
Venue: Journal of biomechanics

Quantifying local aortic stiffness properties in vivo is acknowledged as essential to assess the severity of an ascending thoracic aortic aneurysm (ATAA). Recently, the LESI (local extensional stiffness identification) methodology has been established to quantify non-invasively local stiffness properties of ATAAs using electrocardiographic-gated computed tomography (ECG-gated CT) scans. The aim of the current study was to determine the most sensitive markers of local ATAA stiffness estimation with the hypothesis that direct measures of local ATAA stiffness could better detect the high-risk patients. A cohort of 30 patients (12 BAV and 18 TAV) referred for aortic size evaluation by ECG-gated CT were recruited. For each patient, the extensional stiffness Q was evaluated by the LESI methodology whilst computational flow analyses were also performed to derive hemodynamics markers such as the wall shear stress (WSS). A strong positive correlation was found between the extensional stiffness and the aortic pulse pressure (R = 0.644 and p < 0.001). Interestingly, a significant positive correlation was also found between the extensional stiffness and patients age for BAV ATAAs (R = 0.619 and p = 0.032), but not for TAV ATAAs (R = -0.117 and p = 0.645). No significant correlation was found between the extensional stiffness and WSS evaluated locally. There was no significant difference either in the extensional stiffness between BAV ATAAs and TAV ATAAs (Q = 3.6 ± 2.5 MPa.mm for BAV ATAAs vs Q = 5.3 ± 3.1 MPa.mm for TAV ATAAs, p = 0.094). Future work will focus on relating the extensional stiffness to the patient-specific rupture risk of ATAAs on larger cohorts to confirm the promising interest of the LESI methodology.
Timing of gait events affects whole trajectory analyses: A statistical parametric mapping sensitivity analysis of lower limb biomechanics.
Venue: Journal of biomechanics

Time continuous analyses, such as statistical parametric mapping (SPM), have been increasingly used in biomechanics research to determine differences between populations, interventions and methodologies. Currently, it is not known how sensitive time-continuous analyses are to timing variability that occur in gait data. We evaluated this sensitivity by examining the frequency of significant SPM outcomes between two walking speeds when lower limb kinematics and kinetics were segmented and aligned based on 40 repeatable gait events. These events, defined in the supplementary material, include a commonly used event like foot contact and other events that have been previously demonstrated to be repeatable. Repeatable gait events were determined from joint and segment kinematics, joint kinetics as well as ground reaction forces. We examined the frequency of statistical outcomes for a single subject with different numbers of strides analyzed and for a cohort of 10 subjects. Our findings demonstrate that gait interventions, such as changes in walking speed, can induce temporal shifts that affect time-continuous outcomes for both cohort- and subject-level analyses. As both timing and magnitude are important in gait data, researchers are encouraged to perform additional analyses to understand how both of these variables affect time-continuous analysis outcomes. Finally, we demonstrate that multiple SPM tests can be performed to determine if statistical outcomes are due to temporal shifting or differences in magnitude. It is important to understand how both timing and magnitude of biomechanical data influences time continuous analyses as these analyses inform injury prevention, device development and basic understanding of biomechanics.
Differential biomechanical responses of elastic and muscular arteries to angiotensin II-induced hypertension.
Venue: Journal of biomechanics

Elastic and muscular arteries are distinguished by their distinct microstructures, biomechanical properties, and smooth muscle cell contractile functions. They also exhibit differential remodeling in aging and hypertension. Although regional differences in biomechanical properties have been compared, few studies have quantified biaxial differences in response to hypertension. Here, we contrast passive and active changes in large elastic and medium- and small-sized muscular arteries in adult mice in response to chronic infusion of angiotensin over 14 days. We found a significant increase in wall thickness, both medial and adventitial, in the descending thoracic aorta that associated with trends of an increased collagen:elastin ratio. There was adventitial thickening in the small-sized mesenteric artery, but also significant changes in elastic lamellar structure and contractility. An increased contractile response to phenylephrine coupled with a reduced vasodilatory response to acetylcholine in the mesenteric artery suggested an increased contractile state in response to hypertension. Overall reductions in the calculated gradients in pulse wave velocity and elastin energy storage capability from elastic-to-muscular arteries suggested a possible transfer of excessive pulsatile energy into the small-sized muscular arteries resulting in significant functional consequences in response to hypertension.