nils-herrmann/clean_scirepeval huggingface dataset:
The use of the gait profile score and gait variable score in individuals with Duchenne Muscular Dystrophy.
Venue: Journal of biomechanics

Therapeutic gait interventions for individuals with Duchenne Muscular Dystrophy (DMD) should be based on understanding how movement of the individual is affected and whether different clusters of individuals, determined by clinical severity, differ. Gait indexes have been developed to synthesize the data provided by the three-dimensional (3D) gait analysis such as the Gait Deviation Index (GDI) and the Gait Profile Score (GPS) where the gait variable score (GVS) can be calculated. The objective this study was to evaluate the potential use of the GDI and GPS and MAP using data from 3D gait analysis of DMD patients. The dimension 1 score of the Motor Function Measurement defined the groups that composed the cluster analysis. Twenty patients with DMD composed 2 groups according to the cluster analysis (Cluster 1, n = 10; Cluster 2, n = 10). Three-dimensional gait analysis was conducted where GDI, GPS and GVS (pelvic tilt/obliquity; hip flexion-extension/adduction-abduction/rotation; knee flexion-extension; ankle dorsiflexion-plantarflexion, foot progression angle) were calculated. Cluster 1 group presented lower hip flexion-extension and lower pelvic obliquity when compared with Cluster 2 group (p < 0.05). There was no difference between groups for GDI, GPS total and maximum isometric muscle strength of the lower limbs (p > 0.05). This study showed that GVS could detect alterations on the parameters obtained using three-dimensional gait analysis for those DMD patients separated according to motor function regarding pelvic and hip kinematic patterns. The rehabilitation of patients with DMD is recommended from the early stages of the disease (as Cluster 1, with >MFM) with the hip joint being the therapeutic target.
The feasibility of a split-belt instrumented treadmill running protocol with perturbations.
Venue: Journal of biomechanics

Unexpected perturbations during locomotion can occur during daily life or sports performance. Adequate compensation for such perturbations is crucial in maintaining effective postural control. Studies utilising instrumented treadmills have previously validated perturbed walking protocols, however responses to perturbed running protocols remain less investigated. Therefore, the purpose of this study was to investigate the feasibility of a new instrumented treadmill-perturbed running protocol. Fifteen participants (age = 28 ± 3 years; height = 172 ± 9 cm; weight = 69 ± 10 kg; 60% female) completed an 8-minute running protocol at baseline velocity of 2.5 m/s (9 km/h), whilst 15 one-sided belt perturbations were applied (pre-set perturbation characteristics: 150 ms delay (post-heel contact); 2.0 m/s amplitude; 100 ms duration). Perturbation characteristics and EMG responses were recorded. Bland-Altman analysis (BLA) was employed (bias ± limits of agreement (LOA; bias ± 1.96*SD)) and intra-individual variability of repeated perturbations was assessed via Coefficients of Variation (CV) (mean ± SD). On average, 9.4 ± 2.2 of 15 intended perturbations were successful. Perturbation delay was 143 ± 10 ms, amplitude was 1.7 ± 0.2 m/s and duration was 69 ± 10 ms. BLA showed -7 ± 13 ms for delay, -0.3 ± 0.1 m/s for amplitude and -30 ± 10 ms for duration. CV showed variability of 19 ± 4.5% for delay, 58 ± 12% for amplitude and 30 ± 7% for duration. EMG RMS amplitudes of the legs and trunk ranged from 113 ± 25% to 332 ± 305% when compared to unperturbed gait. This study showed that the application of sudden perturbations during running can be achieved, though with increased variability across individuals. The perturbations with the above characteristics appear to have elicited a neuromuscular response during running.
An optimization method for surgical reduction of hypertrophied inferior turbinate.
Venue: Journal of biomechanics

Surgical reductions of the hypertrophied inferior turbinate (HIT) can improve nasal obstruction. However, there is currently a lack of personalized and objective methods to guide surgical operations, which results in the excessive or inadequate resection of HIT. In this study, we proposed an optimizing method based on homotopy deformation to determine the resected amount and shape of the tissue by matching the flow resistance in the two nasal passageways. The simulation results obtained using computational fluid dynamics showed that after such an optimization procedure, the most obstructed nasal side could have a similar air flux as the less obstructed side. A 35% and a 56% less tissue resection in the optimizing operation compared to that in the total turbinectomy could well balance the air flow between the two nasal cavities in the simulations for patients 1 and 2 with unilateral nasal obstruction respectively. Compared with the optimization operation, the total turbinectomy made a more aggressive resection of HIT, which could worsen the air conditioning capacity of the nose. A sensitivity test indicated that in the optimization operation, the most constricted region in the nasal cavity should be adequately enlarged. However, more tissue resection than is required for the optimization operation did not improve the flow in the obstructed side strikingly. Simulations of the optimization operation in both nasal cavities for a patient with bilateral nasal obstruction were also performed. The flow rate could reach the normal level and be well balanced in the two sides after such an optimization procedure.
Changes in hip mechanics during gait modification to reduce knee abduction moment.
Venue: Journal of biomechanics

First peak knee abduction moment (KAM) has been associated with the severity and progression of knee osteoarthritis (KOA). Gait modifications, including lateral trunk lean (TL), medial knee thrust (MKT), and reduced foot progression (FP) have decreased KAM. However, their effects on the hip joint are poorly understood. Reduced hip abduction moment has been found to be predictive of KOA progression and has been hypothesized to represent a decreased demand on the hip musculature. Lack of studies investigating changes in hip mechanics as a result of gait modification limits our understanding of their cumulative benefit, therefore, we investigated the effects of TL, MKT, and FP on internal hip abduction moment as well as rate change in net joint reaction force. Using real-time visual biofeedback, five trials were completed for each modification. Each modification target range was individualized to 3-5 SD greater (TL and FP) or lesser (MKT) than the participants mean baseline value. Kinematics and kinetics at the hip and knee were calculated at first peak KAM. Trunk lean and MKT decreased hip abduction moment compared to baseline (p < 0.001). Trunk lean increased rate change in net joint reaction force at both the hip (p < 0.001) and knee (p < 0.001) compared to baseline. Additional research is needed to fully understand the effect of gait modifications in a clinical population, particularly the relationship between hip abduction moments and KOA progression. Although interventions such as MKT and TL can be successful in reducing KAM, their effects on hip abduction moment should be considered before clinical implementation.
Effect on manual skills of wearing instrumented gloves during manipulation.
Venue: Journal of biomechanics

Instrumented gloves are motion capture systems that are widely used due to the simplicity of the setup required and the absence of occlusion problems when manipulating objects. Nevertheless, the effect of their use on manipulation capabilities has not been studied to date. Therefore, the aim of this work is to quantify the effect of wearing CyberGlove instrumented gloves on these capabilities when different levels of precision are required. Thirty healthy subjects were asked to perform three standardised dexterity tests twice: bare-handed and wearing instrumented gloves. The tests were the Sollerman Hand Function Test (to evaluate capability of performing activities of daily living), the Box and Block Test (to evaluate gross motor skills) and the Purdue Pegboard Test (to evaluate fine motor skills). Scores obtained in the test evaluating fine motor skills decreased by an average of 29% when wearing gloves, while scores obtained on those evaluating gross motor skills and capability to perform activities of daily living were reduced by an average of 8% and 3%, respectively. The use of instrumented gloves to record hand kinematics is only recommended when performing tasks requiring medium and gross motor skills.
Relationship between intervertebral disc and facet joint degeneration: A probabilistic finite element model study.
Venue: Journal of biomechanics

Both intervertebral disc (IVD) and facet joint (FJ) degeneration are frequently associated with chronic low back pain. While genetic factors are considered the most relevant in the onset of degeneration, the mechanics play an important role in its progression. Degenerative changes in one of these two structures are believed to induce degeneration in the other. However, despite decades of research, there is no consensus on the mechanical interplay between the two structures. On the basis of a parametric finite element model of a human L4-L5 spinal motion segment, one thousand individual segments were probabilistically generated covering all grades of degeneration in both structures. The segments were subjected to combined compression and flexion/extension loads. Correlation matrices were created to identify the effect of individual degeneration parameters of each structure on the mechanical stresses in the corresponding counterpart. In the non-degenerated group, a strong positive and a moderate negative correlation was found between the strain of the capsular ligament and the disc height and the nucleus compressibility, respectively. With increasing degeneration, the correlation between IVD morphologies and the FJ loads gradually decreased, whereas the correlation between FJ morphologies and disc load gradually increased. The results suggest that early mechanical changes associated with IVD degeneration have the greatest effect on the FJ loading. With progression of degeneration, this effect is diminished, whereas the appearance of FJ degeneration increasingly influences the disc loading, which might indicate an increasing support of the disc degeneration.
Biomechanical properties in motion of lumbar spines with degenerative scoliosis.
Venue: Journal of biomechanics

Degenerative lumbar scoliosis presumably alters spinal biomechanics, but a lack of quantitative reference measurements of these spines exists. We aimed to assess the biomechanical properties of spines with degenerative scoliosis, and to relate these to intervertebral disc degeneration (DD) and Cobb angle. Secondly, we compared these results to previous measurements of non-scoliotic spines. Ten cadaveric spines (Th12-L5, mean age 82 ± 11 years) with Cobb angle ≥10° and apex at L3 were acquired. Three loading cycles (-4 to 4 Nm) were applied in flexion/extension (FE), lateral bending (LB), and axial rotation (AR). The range of motion (ROM), neutral zone (NZ) stiffness, NZ ROM, elastic zone (EZ) stiffness and hysteresis were calculated for each motion segment in the loading direction. ROM was calculated in coupled directions, expressed as a percentage of rotation in the loaded direction. For Th12-L5, there was a ROM (degrees ± SD) of 14.9 ± 6.5 in FE, 14.9 ± 7.8 in LB, and 10.2 ± 5.5 in AR. The median (Nm/degree (Q1;Q3)) NZs was 0.24 (0.19;0.35) in FE, 0.25 (0.22;0.42) in LB, and 0.49 (0.33;0.99) in AR. Greater coupled motions related to higher Cobb angle, especially during AR on segments around the apex (FE: ρ = 0.539, p = 0.021 and LB: ρ = 0.821, p = 0.000). DD correlated to lower ROM and increased NZs on L2-L3 in FE (ρ = -0.721, p = 0.028 and ρ = 0.694, p = 0.038, respectively). Compared to non-scoliotic spines, smaller ROM in FE (p = 0.030) was found. This study describes the biomechanical properties of lumbar spines with degenerative scoliosis. Compared to non-scoliotic spines, they tended to be stiffer and exhibited smaller ROM in FE. DD only affected the ROM and NZs of the segments around the apex.
In vivo hip and lumbar spine implant loads during activities in forward bent postures.
Venue: Journal of biomechanics

Long-term measurements on the lumbar spinal alignment during daily life revealed that humans spent 90% of the day in a forward bent posture. Compared to standing, this posture leads to a substantial increase in spinal loading. The lumbar spine and pelvis, however, contribute differently to the total amount of flexion, which could possibly indicate a different timing of maximum loads in both structures during flexion. This study aimed to evaluate the in vivo implant forces in the hip and lumbar spine during activities in forward bent postures. This work utilized data collected in earlier in vivo measurements on patients either with telemeterized hip endoprostheses (HE) or vertebral body replacements (VBR). The following activities were investigated: standing, upper body flexion with and without weights in the hands using different lifting techniques (straight and bent knees). The maximum resultant forces in VBR were considerably lower than in HE. Increases in flexion inclinations caused direct increases of the resultant forces within VBR, followed by a plateau or even a decrease of the force until maximum inclination. The resultant force in HE displayed an almost continuous increase until the maximum inclination. This general curve behavior resulted in different HE-VBR load ratios, which were affected by lifting additional weights or different lifting techniques. The results emphasize that maximum loads in the spine, in contrast to the hip, do not necessarily occur at maximum upper body flexion as normally expected, rather already at intermediate flexion angles in VBR patients. The results form the basis for more detailed insilico analyzes.
In vivo changes in adjacent segment kinematics after lumbar decompression and fusion.
Venue: Journal of biomechanics

The pathogenesis of lumbar adjacent segment disease is thought to be secondary to altered biomechanics resulting from fusion. Direct in vivo evidence for altered biomechanics following lumbar fusion is lacking. This study's aim was to describe in vivo kinematics of the superior adjacent segment relative to the fused segment before and after lumbar fusion. This study analyzed seven patients with symptomatic lumbar degenerative spondylolisthesis (5 M, 2F; age 65 ± 5.1 years) using a biplane radiographic imaging system. Each subject performed two to three trials of continuous flexion of their torso according to established protocols. Synchronized biplane radiographs were acquired at 20 images per second one month before and six months after single-level fusion at L4-L5 or L5-S1, or two-level fusion at L3-L5 or L4-S1. A previously validated volumetric model-based tracking process was used to track the position and orientation of vertebrae in the radiographic images. Intervertebral flexion/extension and AP translation (slip) at the superior adjacent segment were calculated over the entire dynamic flexion activity. Skin-mounted surface markers were tracked using conventional motion analysis and used to determine torso flexion. Change in adjacent segment kinematics after fusion was determined at corresponding angles of dynamic torso flexion. Changes in adjacent segment motion varied across patients, however, all patients maintained or increased the amount of adjacent segment slip or intervertebral flexion/extension. No patients demonstrated both decreased adjacent segment slip and decreased rotation. This study suggests that short-term changes in kinematics at the superior adjacent segment after lumbar fusion appear to be patient-specific.
Maturity offset affects standing postural control in youth male soccer players.
Venue: Journal of biomechanics

Quantifying the response of postural control in developmental athletes makes it possible to understand critical coordination and learning phases and to improve technical-physical interventions. However, the influence of maturation on postural control amongst young soccer players has neither been tested using quantitative methods, nor over a wide age range. In this study, we examined stabilometric parameters of 238 young male soccer players from 9 to 17 years old relative to maturity offset. Two 30-s tests (eyes open and eyes closed) were recorded on a baropodometric platform at 50 Hz. Participants were split into six groups according to their maturity offset, expressed as years from individual's peak height velocity. Dependent variables were: Sway Area, Center-of-Pressure velocity, standard deviation of the antero-posterior and medio-lateral Center-of-Pressure trajectory, Romberg Quotient. Sway Area was significantly higher in players with maturity offset <-1.5 than in groups with maturity offset > 0.5 years (p < 0.001, large effect). Center-of-Pressure velocity markedly dropped in players with maturity offset >-0.5 years (p < 0.001, very large effect). Antero-posterior standard deviation was higher before than after peak height velocity (p < 0.05, large effect) and significantly higher with closed eyes at some points. Medio-lateral standard deviation was higher in the youngest group of players (maturity offset <-2.5 years, large effect) than in those with maturity offset >-0.5 years. In sum, stabilometric parameters improved with age until zero maturity offset was achieved. Thereafter, variables describing postural control in developing soccer players were almost stable. No evidence of a changing role of vision in postural sway control during maturation was observed.
Real-time feedback to reduce low-back load in lifting and lowering.
Venue: Journal of biomechanics

Low-back pain (LBP) is a common health problem. Literature indicates an exposure-response relation between work-related lifting and LBP. Therefore, this study investigated effects of three kinds of real-time feedback on low-back load, quantified as lumbar moments, during lifting. We recruited 97 healthy male and female participants without a recent history of LBP and without prior biomechanical knowledge on lifting. Participants were assigned to groups based on the time of enrollment, filling the four groups in the following order: moment feedback, trunk inclination angle feedback, lumbar flexion feedback, and a control group not receiving feedback. Feedback was given by a sound when a threshold level of the input variable was exceeded. Participants were unaware of the input variable for the feedback, but were instructed to try to avoid the audio feedback by changing their lifting strategy. The groups with feedback were able to reduce the audio feedback and thus changed the input variable towards a more desired level. Lumbar moments significantly decreased over trials in the inclination and moment feedback groups, remained similar in the lumbar flexion group and increased in the control group. Between group comparisons revealed that low-back load was significantly lower in the moment and inclination groups compared to the control group. Additionally, moments were lower in the inclination group than in the lumbar flexion group. Real-time feedback on moments or trunk inclination is a promising tool to reduce low-back load during lifting and lowering.
Sex-dependent differences in lumbo-pelvic coordination for different lifting tasks: A study on asymptomatic adults.
Venue: Journal of biomechanics

During manual material lifting, the sagittal motion is mainly characterized through the lumbo-pelvic coordination, which is quantified by the ratio between the lumbar and hip rotations (L/P ratio). Alteration in the L/P ratio is an important indicator for low back pain (LBP). Previous studies demonstrated sex-dependent differences in LBP prevalence during lifting activities. However, the sex-dependent differences in the L/P ratio during different lifting tasks has to data not been investigated. An optoelectronic system was used to measure the sagittal lumbo-pelvic motion in 10 males and 10 females. Task A was lifting one weight from the ground in front of the body to three target heights with straight knees (A1-3: abdomen, chest and head levels, respectively). Task B was lifting two identical weights from the ground at the sides of the body to three target angles with bended knees (B1-3: arms close and 45° and 90° abducted to the trunk, respectively). Lifts of 10 kg (males and females) and 20 kg (males only) were performed and three phases were investigated: Phase 1 - pure flexion without load, Phase 2 - lifting up weights, Phase 3 - lowering down weights. Females generally displayed a smaller L/P ratio than males. In Phases 2 and 3, the L/P ratio was greater than in Phase 1 for Tasks A and B. The L/P ratio increased with a greater lifting height for Task B, but displayed no difference neither between lifting 10 kg and 20 kg, nor between weight lifting and lowering for both tasks. These results can provide indications for sex-specific recommendations for safer lifting activities.
Analysis of the aerodynamic sound of speech through static vocal tract models of various glottal shapes.
Venue: Journal of biomechanics

The acoustic spectrum of our voice can be divided into harmonic and inharmonic sound components. While the harmonic components, generated by the oscillatory motion of the vocal folds, are well described by reduced-order speech models, the accurate computation of the inharmonic components requires high-order flow simulations, which predict the vortex shedding and turbulent structures present in the shear layers of the glottal jet. This study characterizes the dominant frequencies in the unsteady flow of the intra- and supraglottal region. A realistic vocal tract geometry obtained through magnetic resonance imaging (MRI) is applied for the numerical domain, which is locally modified to account for different convergent and divergent glottal angles. Both time-averaged and fluctuating values of the flow variables are computed and their distribution at various glottal shapes is compared. The impact of the registered modes in the unsteady flow on the acoustic far field is computed through direct compressible flow simulations. Furthermore, acoustic analogies are applied to localize the sources of the aerodynamically generated sound.
A modular impact diverting mechanism for football helmets.
Venue: Journal of biomechanics

To mitigate the injurious effect of the rotational acceleration of the brain, a modular Impact Diverting Mechanism (IDM) has been developed. The IDM can replace stickers (decals) that normally attach to the exterior of a football helmet. The IDM decals reduce friction and catch points between the covered area with the IDM on the outer shell of the helmet and the impacting surface, thereby decreasing rotational acceleration acting on the player's head. A Riddell Speed helmet's exterior was prepared with the IDM and outfitted to a headform equipped with linear accelerometers and gyroscopes. The helmets were tested at an impact velocity of 5.5 m/s at 15°, 30°, and 45° to the vertical: on the front, side, and back of the helmet. Results of 135 impact tests in the lab show that the IDM decal, when compared to helmets without it, reduced the rotational acceleration, rotational velocity, SI, HIC, and RIC ranging from 22% to 77%, 20% to 74%, 13% to 68%, 7% to 68%, 31% to 94%, respectively. Protection against rotational acceleration from oblique impacts is not prioritized in modern football helmets, as evident by current standard helmet testing protocols. This study demonstrates that the inclusion of the IDM decals in football helmets can help reduce the effects of rotational acceleration of the head during oblique impacts.