nils-herrmann/clean_scirepeval huggingface dataset:
A geometry-based model for non-invasive estimation of pressure gradients over iliac artery stenoses.
Venue: Journal of biomechanics

The aim of this study was to develop and verify a model that provides an accurate estimation of the trans-lesion hyperemic pressure gradient in iliac artery stenoses in seconds by only using patient-specific geometric properties obtained from 3-dimensional rotational angiography (3DRA). Twenty-one patients with symptomatic peripheral arterial disease (PAD), iliac artery stenoses and an ultrasound based peak systolic velocity ratio between 2.5 and 5.0 underwent 3DRA and intra-arterial pressure measurements under hyperemic conditions. For each lesion, geometric properties were extracted from the 3DRA images using quantitative vascular analysis software. Hyperemic blood flow was estimated based on stenosis geometry using an empirical relation. The geometrical properties and hyperemic flow were used to estimate the pressure gradient by means of the geometry-based model. The predicted pressure gradients were compared with in vivo measured intra-arterial pressure measurements performed under hyperemic conditions. The developed geometry-based model showed good agreement with the measured hyperemic pressure gradients resulting in a concordance correlation coefficient of 0.86. The mean bias ± 2SD between the geometry-based model and in vivo measurements was comparable to results found by evaluating the actual computational fluid dynamics model (-1.0 ± 14.7 mmHg vs -0.9 ± 12.7 mmHg). The developed model estimates the trans-lesional pressure gradient in seconds without the need for an additional computational fluid dynamics software package. The results justify further study to assess the potential use of a geometry-based model approach to estimate pressure gradient on non-invasive CTA or MRA, thereby reducing the need for diagnostic angiography in patients suffering from PAD.
Use of distraction loading to estimate subject-specific knee ligament slack lengths.
Venue: Journal of biomechanics

Knee ligaments guide and restrain joint motion, and their properties influence joint mechanics. Inverse modeling schemes have been used to estimate specimen-specific ligament properties, where external joint forces are assumed to balance with internal ligament and contact forces. This study simplifies this assumption by adjusting experimental loads to remove internal contact forces. The purpose of this study was to use novel experimental loading in an inverse modeling scheme to estimate ligament slack lengths, perform validation using additional loading scenarios, and evaluate sensitivity to the applied loading. Joint kinematics and kinetics were experimentally measured for a set of load cases. An optimization scheme used a specimen-specific forward kinematics model to estimate ligament slack lengths by minimizing the residual between model and experimentally measured kinetics. The calibrated model was used for a form of validation by evaluating non-optimized load cases. Additionally, uncertainty analysis related kinetic errors to previously reported kinematic errors. The six DOF tibial reactions realized RMS errors less than 23 N and 0.75 Nm for optimized load cases, and 33 N and 2.25 Nm for the non-optimized load cases. The uncertainty analysis, which was performed using the optimized load cases, showed average kinetic RMS errors less than 26 N and 0.45 Nm. The model's recruitment patterns were similar to those found in clinical and cadaveric studies. This study demonstrated that experimental distraction loading can be used in an inverse modeling scheme to estimate ligament slack lengths with a forward kinematics model.
Increasing step width reduces the requirements for subtalar joint moments and powers.
Venue: Journal of biomechanics

The subtalar joint (STJ) contributes to the absorption and generation of mechanical energy (and power) during walking to maintain frontal plane stability. Previous observational studies have suggested that there may be a relationship between step width and STJ supination moment. This study directly tests the hypothesis that walking with a step width greater than preferred would reduce STJ moments, energy absorption, and power generation requirements, while increasing energy absorption at the hip during initial contact. Participants (n = 12, 7 females) were asked to walk on an instrumented treadmill at a constant velocity and cadence at a range of fixed step widths ranging from 0.1 to 0.4 times leg length (L). Walking at step widths greater than preferred (0.149 ± 0.04 L) reduced peak STJ moments at initial contact and propulsion which subsequently reduced the negative and positive work performed at the STJ. There was a 43% reduction in energy absorption (negative work) and approximately 30% decrease in positive work at the STJ as step width increased from 0.1 L to 0.4 L. An increase in energy absorption at the knee and hip was evident with an increase in step width during initial contact, although minimal mechanical changes were observed at the proximal joints during propulsion. These results suggest an increase in step width reduces the forces generated by muscles at the STJ across stance and is therefore likely to be beneficial in the prevention and treatment of their injuries. In terms of rehabilitation, the increase in mechanical costs occurring due to an increase in energy absorption by the hip and knee is of minimal concern.
The sensitivity to inter-subject variability of the bridging vein entry angles for prediction of acute subdural hematoma.
Venue: Journal of biomechanics

Acute subdural hematoma (ASDH) is one of the most frequent traumatic brain injuries (TBIs) with high mortality rate. Bridging vein (BV) ruptures is a major cause of ASDH. The KTH finite element head model includes bridging veins to predict acute subdural hematoma due to BV rupture. In this model, BVs were positioned according to Oka et al. (1985). The aim of the current study is to investigate whether the location and entry angles of these BVs could be modelled using data from a greater statistical sample, and what the impact of this improvement would be on the model's predictive capability of BV rupture. From the CT angiogram data of 78 patients, the relative position of the bridging veins and their entry angles along the superior sagittal sinus was determined. The bridging veins were repositioned in the model accordingly. The performance of the model, w.r.t. BV rupture prediction potential was tested on simulations of full body cadaver head impact experiments. The experiments were simulated on the original version of the model and on three other versions which had updated BV positions according to mean, maximum and minimum entry angles. Even though the successful prediction rate between the models stayed the same, the location of the rupture site significantly improved for the model with the mean entry angles. Moreover, the models with maximum and minimum entry angles give an insight of how BV biovariability can influence ASDH. In order to further improve the successful prediction rate, more biofidelic data are needed both with respect to bridging vein material properties and geometry. Furthermore, more experimental data are needed in order to investigate the behaviour of FE head models in depth.
Soft tissue stiffness over the hip increases with age and its implication in hip fracture risk in older adults.
Venue: Journal of biomechanics

Risk of hip fracture depends on the bone strength as well as the impact force delivered to the proximal femur during falls, and femoral soft tissue may help to reduce the hip fracture risk by attenuating the impact force. Femoral soft tissue stiffness was measured from a large sample, and compared how this was affected by age, gender and site. One hundred fifty healthy individuals (fifty-two young (aged between 19 and 29), forty-eight middle-aged (30-64), and fifty old (over 65)) participated. Each age group included an equal number of males and females. Using an automated hand-held indentation device, soft tissue stiffness was measured over twelve sites with respect to the greater trochanter (GT). For both left and right hips, the stiffness was associated with age (p < 0.0005), gender (p < 0.0005), and site (p < 0.0005). On average, the stiffness was 26% greater in older than young adults (321.5 versus 254.3 N/m). On average across twelve sites, the regression analysis indicated that the stiffness increases 1.33 N/m every year ("soft tissue stiffness over the hip = 1.33*age + 221.8"; R = 0.518, p < 0.0005). Furthermore, the stiffness was 18% greater in male than female (308.8 versus 262.6 N/m), and differed across twelve sites over the hip, being greatest (424.2 N/m) at the GT, and least (206.3 N/m) at the superior gluteal region. The results provide insights into the shock absorbing property of soft tissue over the hip, and inform the improvement of fall-related injury prevention interventions (i.e., hip protector, safe landing strategies) in older adults.
A viscoelastic ellipsoidal model of the mechanics of plantar tissues.
Venue: Journal of biomechanics

Several assessments of the mechanics of plantar tissues, using various material models in conjunction with representing plantar regions using simple geometry, have been proposed. In this study, the plantar tissues were divided into eight regions to account for the various tissue characteristics. The plantar tissue model described each region as an ellipsoid, with a viscoelastic material model. The model combined varying elliptical contact areas with nonlinear tissue stiffness and damping. The main instruments used in this research were pressure-measuring insoles, which were used to determine the ground reaction force, as well as contact areas. The measured contact areas were fitted as elliptical areas to describe the compression of the corresponding ellipsoids. The approach was tested using walking data collected from 26 individuals: four men, 22 women, 24.4 ± 6.9 years old, 66.9 ± 21.4 kg of mass, 1.66 ± 0.12 m tall. The geometric and material variables of the proposed ellipsoidal model were optimized for each participant to match the ground reaction forces. Results suggest that the ellipsoid model is able to reproduce ground reaction force with reasonable accuracy. The largest errors were seen in heel and toe regions and were due to high-rate forces and small comparative areas, respectively. The model also showed that there are regional differences in the mechanical characteristics of plantar tissue, which confirms earlier research.
Gait stride-to-stride variability and foot clearance pattern analysis in Idiopathic Parkinson's Disease and Vascular Parkinsonism.
Venue: Journal of biomechanics

The literature on gait analysis in Vascular Parkinsonism (VaP), addressing issues such as variability, foot clearance patterns, and the effect of levodopa, is scarce. This study investigates whether spatiotemporal, foot clearance and stride-to-stride variability analysis can discriminate VaP, and responsiveness to levodopa. Fifteen healthy subjects, 15 Idiopathic Parkinson's Disease (IPD) patients and 15 VaP patients, were assessed in two phases: before (Off-state), and one hour after (On-state) the acute administration of a suprathreshold (1.5 times the usual) levodopa dose. Participants were asked to walk a 30-meter continuous course at a self-selected walking speed while wearing foot-worn inertial sensors. For each gait variable, mean, coefficient of variation (CV), and standard deviations SD1 and SD2 obtained by Poincaré analysis were calculated. General linear models (GLMs) were used to identify group differences. Patients were subject to neuropsychological evaluation (MoCA test) and Brain MRI. VaP patients presented lower mean stride velocity, stride length, lift-off and strike angle, and height of maximum toe (later swing) (p < .05), and higher %gait cycle in double support, with only the latter unresponsive to levodopa. VaP patients also presented higher CV, significantly reduced after levodopa. Yet, all VaP versus IPD differences lost significance when accounting for mean stride length as a covariate. In conclusion, VaP patients presented a unique gait with reduced degrees of foot clearance, probably correlated to vascular lesioning in dopaminergic/non-dopaminergic cortical and subcortical non-dopaminergic networks, still amenable to benefit from levodopa. The dependency of gait and foot clearance and variability deficits from stride length deserves future clarification.
Late swing running mechanics influence hamstring injury susceptibility in elite rugby athletes: A prospective exploratory analysis.
Venue: Journal of biomechanics

Hamstring injuries are one of the most prevalent injuries in rugby union and many other running-based sports, such as track sprinting and soccer. The majority of these injuries occur during running; however, the relationship between running mechanics and hamstring injury is unclear. Obtaining large samples of prospective injury data to examine this relationship is difficult, and therefore exploratory analysis frameworks may assist in deriving valuable information from studies with small but novel samples. The aim of this study was to undertake a prospective exploratory analysis of the relationship between running mechanics and hamstring injury. Kinematic and kinetic data of the trunk, pelvis and lower limbs were collected during maximal overground running efforts for ten elite rugby union athletes. Subsequently, hamstring injury occurrence was recorded for the following Super Rugby season, during which three athletes sustained a running-based hamstring injury. Functional principal component analysis was used to visualise patterns of variability in running mechanics during the late swing phase between athletes. Results indicated that subsequently injured athletes demonstrated a tendency for greater thoracic lateral flexion, greater hip extension moments and greater knee power absorption, compared to uninjured athletes. All variables demonstrated an ability to descriptively differentiate between injured and uninjured athletes at approximately 60% of the late swing phase. Therefore, we hypothesize that greater thoracic lateral flexion, a greater hip extension moment and greater knee power absorption between peak hip flexion and peak knee extension during the late swing phase may put rugby athletes at greater risk of running-based hamstring injury.
Kinematic and EMG analysis of horizontal bimanual climbing in humans.
Venue: Journal of biomechanics

Climbing is an increasingly popular recreational and competitive behavior, engaged in a variety of environments and styles. However, injury rates are high in climbing populations, especially in the upper extremity and shoulder. Despite likely arising from an arboreal, climbing ancestor and being closely related to primates that are highly proficient climbers, the modern human shoulder has devolved a capacity for climbing. Limited biomechanical research exists on manual climbing performance. This study assessed kinematic and muscular demands during a bimanual climbing task that mimicked previous work on climbing primates. Thirty participants were recruited - 15 experienced and 15 inexperienced climbers. Motion capture and electromyography (EMG) measured elbow, thoracohumeral and trunk angles, and activity of twelve shoulder muscles, respectively, of the right-side while participants traversed across a horizontal climbing apparatus. Statistical parametric mapping was used to detect differences between groups in kinematics and muscle activity. Experienced climbers presented different joint motions that more closely mimicked the kinematics of climbing primates, including more elbow flexion (p = 0.0045) and internal rotation (p = 0.021), and less thoracohumeral elevation (p = 0.046). Similarly, like climbing primates, experienced climbers generally activated the shoulder musculature at a lower percentage of maximum, particularly during the exchange from support to swing and swing to support phase. However, high muscle activity was recorded in all muscles in both participant groups. Climbing experience coincided with a positive training effect, but not enough to overcome the high muscular workload of bimanual climbing. Owing to the evolved primary usage of the upper extremity for low-force, below shoulder-height tasks, bimanual climbing may induce high risk of fatigue-related musculoskeletal disorders.
Accuracy of biplane videoradiography for quantifying dynamic wrist kinematics.
Venue: Journal of biomechanics

Accurately assessing the dynamic kinematics of the skeletal wrist could advance our understanding of the normal and pathological wrist. Biplane videoradiography (BVR) has allowed investigators to study dynamic activities in the knee, hip, and shoulder joint; however, currently, BVR has not been utilized for the wrist joint because of the challenges associated with imaging multiple overlapping bones. Therefore, our aim was to develop a BVR procedure and to quantify its accuracy for evaluation of wrist kinematics. BVR was performed on six cadaveric forearms for one neutral static and six dynamic tasks, including flexion-extension, radial-ulnar deviation, circumduction, pronation, supination, and hammering. Optical motion capture (OMC) served as the gold standard for assessing accuracy. We propose a feedforward tracking methodology, which uses a combined model of metacarpals (second and third) for initialization of the third metacarpal (MC3). BVR-calculated kinematic parameters were found to be consistent with the OMC-calculated parameters, and the BVR/OMC agreement had submillimeter and sub-degree biases in tracking individual bones as well as the overall joint's rotation and translation. All dynamic tasks (except pronation task) showed a limit of agreement within 1.5° for overall rotation, and within 1.3 mm for overall translations. Pronation task had a 2.1° and 1.4 mm limit of agreement for rotation and translation measurement. The poorest precision was achieved in calculating the pronation-supination angle, and radial-ulnar and volar-dorsal translational components, although they were sub-degree and submillimeter. The methodology described herein may assist those interested in examining the complexities of skeletal wrist function during dynamic tasks.
Quantifying physical functional trajectory in hospitalized older adults using body worn inertial sensors.
Venue: Journal of biomechanics

Acute medical illness requiring hospitalization usually is a critical event in the trajectory leading to disability in older adults. Functional decline frequently occurs during hospitalization, resulting in a loss of Independence in activities of daily living after discharge. The aim of the study was to assess the functional decline in different ADLs of hospitalized elderly patients in an Acute Care for Elderly (ACE) unit incorporating a body-worn inertial sensor and accompanying custom algorithms. 38 hospitalized older adults (age ≥ 75) were included. The patients completed different functional tasks, including a balance test, Gait Velocity Test (GVT), verbal and arithmetic dual-task gait, and a sit-to-stand ability test at admission and discharge. Movement-related parameters were acquired from a unique tri-axial inertial sensor unit. Maximal muscle strength and muscle power output endpoints were also assessed. The results indicated that significant improvements (p < 0.05) were found at discharge compared with the admission values for gait variability and spatiotemporal parameters in the 4- and 6-meter GVT. These significant gains were also obtained in the verbal GVT. In contrast, a significant reduction was found in the functional status measured with the Barthel Index scale. Regarding to the sit-to-stand ability, lower peak power was observed in the sit-to-stand phase of the task at discharge. In conclusion, inertial sensor unit and our custom, validated, algorithms represent a feasible tool for measuring and monitoring functional trajectory during hospitalization in older adults and they are sensitive to detect differences in movement pattern parameters in different ADLs such as walking and the ability to stand from a seated position.
The effect of isokinetic dynamometer deceleration phase on maximum ankle joint range of motion and plantar flexor mechanical properties tested at different angular velocities.
Venue: Journal of biomechanics

During range of motion (max-ROM) tests performed on an isokinetic dynamometer, the mechanical delay between the button press (by the participant to signal their max-ROM) and the stopping of joint rotation resulting from system inertia induces errors in both max-ROM and maximum passive joint moment. The present study aimed to quantify these errors by comparing data when max-ROM was obtained from the joint position data, as usual (max-ROMPOS), to data where max-ROM was defined as the first point of dynamometer arm deceleration (max-ROMACC). Fifteen participants performed isokinetic ankle joint max-ROM tests at 5, 30 and 60° s-1. ROM, peak passive joint moment, end-range musculo-articular (MAC) stiffness and area under the joint moment-position curve were calculated. Greater max-ROM was observed in max-ROMPOS than max-ROMACC (P < 0.01) at 5 (0.2 ± 0.15%), 30 (1.8 ± 1.0%) and 60° s-1 (5.9 ± 2.3%), with the greatest error at the fastest velocity. Peak passive moment was greater and end-range MAC stiffness lower in max-ROMPOS than in max-ROMACC only at 60° s-1 (P < 0.01), whilst greater elastic energy storage was found at all velocities. Max-ROM and peak passive moment are affected by the delay between button press and eventual stopping of joint rotation in an angular velocity-dependent manner. This affects other variables calculated from the data. When high data accuracy is required, especially at fast joint rotation velocities (≥30° s-1), max-ROM (and associated measures calculated from joint moment data) should be taken at the point of first change in acceleration rather than at the dynamometer's ultimate joint position.
Gait modification when decreasing double support percentage.
Venue: Journal of biomechanics

Much is still unknown about walking stability, including which aspects of gait contribute to higher stability. Walking stability appears to be related to walking speed, although the exact relationship is unclear. As walking speed decreases, the double support (DS) period of gait increases both in time and as a percentage of the gait cycle. Because humans have more control over their center of mass movement during DS, increasing DS duration may alter stability. This study examined how human gait is affected by changing DS percentage independent of walking speed. Sixteen young, healthy adults walked on a treadmill at a single speed for six one-minute trials. These trials included normal gait as well as longer- and shorter-than-normal DS percentage gaits. Subjects were consistently able to decrease DS percentage but had difficulty increasing DS percentage. In some cases, subjects altered their cadence when changing DS percentage, particularly when attempting to increase DS percentage. The changes to gait when decreasing DS percentage were similar to changes when increasing walking speed but occurred mainly during the swing period. These changes include increased hip and knee flexion during the swing period, increased swing foot height, and larger magnitude peaks in ground reaction forces. The changes in gait when attempting to increase DS percentage trended toward changes when decreasing walking speed. Altering DS percentage induced gait changes that were similar to, yet clearly distinct from, gait changes due to walking speed. Further, the difficulty of increasing DS percentage when walking at a constant speed suggests that people walk more slowly when they want to increase time spent in DS.