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Purpose: Accurate detection of microcalcifications ( µ Calcs ) is crucial for the early detection of breast cancer. Some clinical studies have indicated that digital breast tomosynthesis (DBT) systems with a wide angular range have inferior µ Calc detectability compared with those with a narrow angular range. This study aims to (1) provide guidance for optimizing wide-angle (WA) DBT for improving µ Calcs detectability and (2) prioritize key optimization factors. Approach: An in-silico DBT pipeline was constructed to evaluate µ Calc detectability of a WA DBT system under various imaging conditions: focal spot motion (FSM), angular dose distribution (ADS), detector pixel pitch, and detector electronic noise (EN). Images were simulated using a digital anthropomorphic breast phantom inserted with 120 µ m µ Calc clusters. Evaluation metrics included the signal-to-noise ratio (SNR) of the filtered channel observer and the area under the receiver operator curve (AUC) of multiple-reader multiple-case analysis. Results: Results showed that FSM degraded µ Calcs sharpness and decreased the SNR and AUC by 5.2% and 1.8%, respectively. Non-uniform ADS increased the SNR by 62.8% and the AUC by 10.2% for filtered backprojection reconstruction with a typical clinical filter setting. When EN decreased from 2000 to 200 electrons, the SNR and AUC increased by 21.6% and 5.0%, respectively. Decreasing the detector pixel pitch from 85 to 50 µ m improved the SNR and AUC by 55.6% and 7.5%, respectively. The combined improvement of a 50 µ m pixel pitch and EN200 was 89.2% in the SNR and 12.8% in the AUC. Conclusions: Based on the magnitude of impact, the priority for enhancing µ Calc detectability in WA DBT is as follows: (1) utilizing detectors with a small pixel pitch and low EN level, (2) allocating a higher dose to central projections, and (3) reducing FSM. The results from this study can potentially provide guidance for DBT system optimization in the future.
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Passive exoskeleton chairs can alleviate fatigue, enhance efficiency, and reduce the risk of musculoskeletal diseases for workers standing for prolonged hours and have gradually been applied in recent years. In this study, by strategically distributing elastic and non-elastic fabrics, physical interfaces of the attachment system for the exoskeleton chair were revised to better adapt to bodily deformations and movements. We conducted an experiment using motion capture systems and subjective questionnaires to evaluate the performance of the initial and revised attachment systems of an exoskeleton chair worn by participants while performing multiple simulated assembly tasks. The results indicated that when wearing the revised one, some adverse effects on gait were significant reduced, as was the relative displacement of straps and discomfort in lumbar and abdominal, and system usability was improved, all of which were considered to be helpful in design to improve the performance of the attachment system in the future.
This study aims to address the limited adaptability of the physical interface of attachment system (AS) to movements and bodily deformations. We proposed a revised AS by strategically incorporating elastic and non-elastic fabrics. Our results indicate that the revised AS alleviates negative effects on gait and discomfort, and improves overall usability.
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PURPOSE: The appropriate extrication techniques for trauma patients after car accidents remain a topic of controversy. Various techniques for immobilizing the cervical spine during prehospital extrication have been investigated. METHODS: This explorative study compared the amount of spinal motion during five different extrication procedures from a racecar and a rallycar performed by two teams: a professional motorsport extrication team and a team of professional emergency medical technicians (EMTs). Two different microelectromechanical systems were used to measure spinal motion, and a motionscore was calculated to compare the amount of remaining spinal motion. A high motionscore indicates high remaining motion and a low motionscore indicates low remaining motion. RESULTS: The use of an extricable seat results in a mean overall motion score of 1617 [95% CI 308-2926]. Emergency extrication without equipment resulted in the lowest overall motionscore 1448 [95% CI 1070-1826]. In case of urgent extrication the Extrication team attained a motionscore of 2118 [95% CI 517-3718] and the EMT team a motionscore of 2932 [95% CI 1427-4435]. When performing the procedure with the aid of a rescue boa, the EMT team achieved an overall mean motionscore in the same range 2725 [95% CI 568-4881] with boa vs. 2932 [95% CI 1427-4435] without boa. When mean scores of individual spinal segments were analyzed, we found that the EMT team did especially worse in immobilizing the cervical spine 198 vs. 758. CONCLUSIONS: Regular training of extrication procedures has paid off considerably in reducing spinal movement during extrication from a racecar. If an extricable seat is available, extrication should be performed using it. However, if emergency extrication is necessary, an additional manual cervical spine immobilization should be conducted using the Rautek maneuver to sufficiently reduce cervical spine movement.
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Eustachian tube dysfunction (ETD) poses diagnostic challenges due to its complex pathophysiology and varied clinical presentation. Traditional diagnostic methods often lack direct visualization of the Eustachian tube (ET) function, leading to suboptimal evaluation and management. Dynamic slow-motion video endoscopy (DSVE) has emerged as a novel approach to address these limitations, offering real-time visualization of ET dynamics with enhanced clarity and precision. This comprehensive review provides an overview of DSVE as a promising tool for evaluating ETD. We discuss its methodology, clinical applications, comparative analysis with traditional methods, and future directions. Key findings from the literature highlight DSVE's ability to enhance diagnostic accuracy, facilitate targeted treatment strategies, and improve patient outcomes. Integrating DSVE into routine clinical practice holds significant implications for the diagnosis and management of ETD, offering clinicians valuable insights into underlying pathophysiology and guiding personalized treatment interventions. Future research should focus on standardizing DSVE protocols, validating its diagnostic accuracy, and exploring its role in guiding novel treatment modalities. By advancing our understanding of ETD and optimizing diagnostic and therapeutic approaches, DSVE has the potential to revolutionize the management of this common yet challenging otologic condition.
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Background: Interventions using vibration stimulation have been recognized for their potential for increasing range of motion (ROM) without compromising muscle strength. Handheld vibration massagers can efficiently deliver vibration therapy to the shoulder joint and may be a potential treatment. Purpose: To evaluate the effects of vibration massage using a handheld device on the soft tissues of the posterior shoulder joint, particularly on internal rotation (IR) passive ROM and external rotation (ER) muscle strength. Study Design: Crossover study design. Methods: A crossover study with a 5-min vibration massage and passive control condition was conducted in healthy male volunteers (mean age 20.5 ± 1.7 years). Vibration massage was applied to the posterior shoulder soft tissues of the dominant arm, with no intervention under control conditions. IR-ROM (vertebral level and in abduction) and strength of the external rotators (isometric and isokinetic) were measured before and immediately after the intervention. Vertebral levels were calculated as a ratio of lengths (ratio decreases with increased mobility). IR-ROM in abduction, the angle was measured. Statistical analysis was performed with two-way repeated measures ANOVA and paired t-test (Bonferroni correction). Results: Vibration application decreased (improved) vertebral level IR ROM by -4.1% (p < 0.01, d = 0.445) and increased abduction position IR ROM by 11.4° (p < 0.01, d = 0.694). These changes exceeded the 95% confidence interval for the minimum detectable change. By contrast, the control condition produced no changes. IR-ROM (vertebral level and abduction) immediately after the intervention showed significant differences between the control and vibration conditions (p = 0.036, d = 0.273; p = 0.048, d = 0.483, respectively). Muscle strength did not show any interaction, time, or between-condition effects. Conclusions: A massage using a handheld vibration massager applied to the posterior shoulder soft tissues increased IR-ROM without negatively affecting muscle strength, suggesting its potential use as a means of warming up. Level of Evidence: Level 3.
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Background: Joint range of motion based on the neutral null method, muscle strength based on manual muscle testing, and selective voluntary motor control based on selective control assessment of the lower extremity are standard parameters of a pediatric three-dimensional clinical gait analysis. Lower-limb reference data of children are necessary to identify and quantify abnormalities, but these are limited and when present restricted to specific joints or muscles. Methods: This is the first study that encompasses the aforementioned parameters from a single group of 34 typically developing children aged 5-17 years. Left and right values were averaged for each participant, and then the mean and standard deviation calculated for the entire sample. The data set was tested for statistical significance (p < 0.05). Results: Joint angle reference values are mostly consistent with previously published standards, although there is a large variability in the existing literature. All muscle strength distributions, except for M. quadriceps femoris, differ significantly from the maximum value of 5. The mean number of repetitions of heel-rise test is 12 ± 5. Selective voluntary motor control shows that all distributions, except for M. quadriceps femoris, differ significantly from the maximum value of 2. Conclusion: Since typically developing children do not match expectations and reference values from the available literature and clinical use, this study emphasizes the importance of normative data. Excessively high expectations lead to typically developing children being falsely underestimated and affected children being rated too low. This is of great relevance for therapists and clinicians. Level of evidence: 3.
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Introduction: As motion capture technology becomes more popular for athlete monitoring and return-to-play evaluation, it is imperative that trunk mechanics are modeled similarly across participants. The purpose of this study was to determine how adjusting marker placement at the sternum or removing potentially occluded markers for purposes of tracking the trunk segment influences trunk kinematics during gait and a drop vertical jump (DVJ). Methods: Sagittal plane trunk angles of 18 participants were computed for a Definition Model and three trunk model variations. Model variations were specifically chosen to avoid difficulties with placement of the sternum and/or thorax markers in female participants due to sports bra coverage and/or occlusion. Intraclass correlation coefficients were computed per trunk model variation to determine agreement with the Definition Model. Results: The Mid-Sternum model, in which the xiphoid process marker was adjusted to the midpoint of the xiphoid process and jugular notch, exhibited the least discrepancies and excellent agreement with the Definition Model across both tasks. Alternatively, the No-Thorax model, in which the thorax marker was removed, exhibited the greatest kinematic differences during the DVJ and moderate to excellent agreement across both tasks. Conclusion: The marker set chosen to track trunk motion during dynamic tasks must include locations that can be placed similarly on all participants. Based on these findings, the xiphoid process marker may be adjusted superiorly prior to the collection of dynamic trials. The recommended model for tracking the trunk segment includes marker placements on the jugular notch, mid-sternum, and 1st and 10th thoracic spinous processes.
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BACKGROUND: Markerless motion capture (MMC) uses video cameras or depth sensors for full body tracking and presents a promising approach for objectively and unobtrusively monitoring functional performance within community settings, to aid clinical decision-making in neurodegenerative diseases such as dementia. OBJECTIVE: The primary objective of this systematic review was to investigate the application of MMC using full-body tracking, to quantify functional performance in people with dementia, mild cognitive impairment, and Parkinson disease. METHODS: A systematic search of the Embase, MEDLINE, CINAHL, and Scopus databases was conducted between November 2022 and February 2023, which yielded a total of 1595 results. The inclusion criteria were MMC and full-body tracking. A total of 157 studies were included for full-text screening, out of which 26 eligible studies that met the selection criteria were included in the review.â¯. RESULTS: Primarily, the selected studies focused on gait analysis (n=24), while other functional tasks, such as sit to stand (n=5) and stepping in place (n=1), were also explored. However, activities of daily living were not evaluated in any of the included studies. MMC models varied across the studies, encompassing depth cameras (n=18) versus standard video cameras (n=5) or mobile phone cameras (n=2) with postprocessing using deep learning models. However, only 6 studies conducted rigorous comparisons with established gold-standard motion capture models. CONCLUSIONS: Despite its potential as an effective tool for analyzing movement and posture in individuals with dementia, mild cognitive impairment, and Parkinson disease, further research is required to establish the clinical usefulness of MMC in quantifying mobility and functional performance in the real world.
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Cognitive Dysfunction , Motion Capture , Humans , Activities of Daily Living , Cognitive Dysfunction/physiopathology , Cognitive Dysfunction/diagnosis , Dementia/physiopathology , Dementia/diagnosis , Motion Capture/methods , Neurodegenerative Diseases/physiopathology , Parkinson Disease/physiopathology , Physical Functional PerformanceABSTRACT
Background: There is increasing focus on the development of high-quality simulation models for medical education. Cadaveric models, although considered more realistic, may be difficult to obtain and costly. The advent of three-dimensional (3D) printing has offered a low-cost, reliable, and reproducible alternative. This study sought to compare the utility of 3D-printed to cadaveric models for training in transcutaneous injection laryngoplasty (TIL). Methods: A simulation course with a cross-over design was employed. Video laryngoscopes were utilized for both the 3D and cadaveric models to assess the accuracy of injection into the vocal fold. Pre-procedure and post-procedure surveys were administered to evaluate understanding and comfort level on a Likert scale of 1-10. Each model was also rated on a 1-5 Likert scale for self-efficacy, fidelity, and educational value. Results: Pre- and post-survey data were completed by 15 otolaryngology residents and medical students. Mean pre-seminar understanding and comfort level were 3.7 and 2.2, respectively, compared to 6.9 and 5.9 (p < .05) following use of the 3D model and 6.4 and 4.7 (p < .05) following use of the cadaver model. When comparing 3D and cadaveric models, no significant differences were observed regarding self-efficacy, fidelity, and educational value. Conclusion: There was a similar mean increase in understanding and comfort following use of the 3D and cadaveric models. 3D-printing can provide an excellent adjunct to, and eventually a potential replacement for hands-on cadaveric training in medical education, particularly for TIL. Level of Evidence: Level III.
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Introduction: This study examines a set of oculomotor measurements, or "oculometric" biomarkers, as potential early indicators of visual and visuomotor deficits due to retinal toxicity in asymptomatic Systemic Lupus Erythematosus (SLE) patients on long-term hydroxychloroquine (HCQ) treatment. The aim is to identify subclinical functional impairments that are otherwise undetectable by standard clinical tests and to link them to structural retinal changes. Methods: We measured oculomotor responses in a cohort of SLE patients on chronic HCQ therapy using a previously established behavioral task and analysis technique. We also examined the relationship between oculometrics, OCT measures of retinal thickness, and standard clinical perimetry measures of visual function in our patient group using Bivariate Pearson Correlation and a Linear Mixed-Effects Model (LMM). Results: Significant visual and visuomotor deficits were found in 12 asymptomatic SLE patients on long-term HCQ therapy compared to a cohort of 17 age-matched healthy controls. Notably, six oculometrics were significantly different. The median initial pursuit acceleration was 22%, steady-state pursuit gain 16%, proportion smooth 7%, and target speed responsiveness 31% lower, while catch-up saccade amplitude was 46% and fixation error 46% larger. Excluding the two patients with diagnosed mild toxicity, four oculometrics, all but fixation error and proportion smooth, remained significantly impaired compared to controls. Across our population of 12 patients (24 retinae), we found that pursuit latency, initial acceleration, steady-state gain, and fixation error were linearly related to retinal thickness even when age was accounted for, while standard measures of clinical function (Mean Deviation and Pattern Standard Deviation) were not. Discussion: Our data show that specific oculometrics are sensitive early biomarkers of functional deficits in SLE patients on HCQ that could be harnessed to assist in the early detection of HCQ-induced retinal toxicity and other visual pathologies, potentially providing early diagnostic value beyond standard visual field and OCT evaluations.
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Inspired by the motion processing pathway, this paper proposes a bio-inspired feedforward spiking network model based on Hodgkin-Huxley neurons for human motion perception. The proposed network mimics the mechanisms of direction selectivity found in simple and complex cells of the primary visual cortex. Simple cells' receptive fields are modeled using Gabor energy filters, while complex cells' receptive fields are constructed by integrating the responses of simple cells in an energy model. To generate the motion map, the spiking output of the network integrates motion information encoded by the responses of complex cells with various preferred directions. Simulation results demonstrate that the spiking neuron-based network effectively replicates the directional selectivity operation of the visual cortex when presented with a sequence of time-varying images. We evaluate the proposed model against state-of-the-art spiking neuron-based motion detection models using publicly available datasets. The results highlight the model's capability to extract motion energy from diverse video sequences, akin to human visual motion perception models. Additionally, we showcase the application of the proposed model in motion segmentation tasks and compare its performance with state-of-the-art motion-based segmentation models using challenging video segmentation benchmarks. The results indicate competitive performance. The motion maps generated by the proposed model can be utilized for action recognition in input videos.
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Visual stimulation can generate illusory self-motion perception (vection) and cause motion sickness among susceptible people, but the underlying neural mechanism is not fully understood. In this study, SSVEP responses to visual stimuli presented in different parts of the visual field are examined in individuals with different susceptibilities to motion sickness to identify correlates of motion sickness. Alpha band SSVEP data were collected from fifteen university students when they were watching roll-vection-inducing visual stimulation containing: (1) an achromatic checkerboard flickering at 8.6 Hz in the central visual field (CVF) and (2) rotating dots pattern flickering at 12 Hz in the peripheral visual field. Rotating visual stimuli provoked explicit roll-vection perception in all participants. The motion sickness resistant participants showed reduced SSVEP response to CVF checkerboard during vection, while the motion sickness susceptible participants showed increased SSVEP response. The changes of SSVEP in the presence of vection significantly correlated with individual motion sickness susceptibility and rated scores on simulator sickness symptoms. Discussion on how the findings can support the sensory conflict theory is presented. Results offer a new perspective on vection and motion sickness susceptibility. Supplementary Information: The online version contains supplementary material available at 10.1007/s11571-023-09991-7.
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This work investigates the use of a multi-2D cine magnetic resonance imaging-based comprehensive motion monitoring (CMM) system for the assessment of prostate intrafraction 3D drifts. The data of six healthy volunteers were analyzed and the values of a clinically-relevant registration quality factor metric exported by CMM were presented. Additionally, the CMM-derived prostate motion was compared to a 3D-based reference and the 2D-3D tracking agreement was reported. Due to the low quality of SI motion tracking (often > 2 mm tracking mismatch between anatomical planes) we conclude that further improvements are desirable prior to clinical introduction of CMM for prostate drift corrections.
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A multi-orbital ionic Hamiltonian is presented to analyze the many-body properties of the d-transition metal atoms. This Hamiltonian considers all the atomic states obeying the first Hund´s rule and also includes all orbital degeneracy, as well as the interaction of the atom with a metal. We analyze the solution of this ionic Hamiltonian by means of the Equation of Motion (EOM) method up to the fourth order, V4, in the atom-metal interaction. Equations for the appropriate Green-functions for analyzing the chemical and transport properties of the system are given for different atom occupancies. In particular, we introduce a full analysis of the multi-orbital Hamiltonian including atomic configurations with N, N+1 and N-1 electrons, and discuss its Kondo properties. The shells d1, d2 and d3 are analyzed in detail and Kondo energies are deduced in all these cases showing good agreement with the conventional known results. .
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Keeping visual space constant across movements of the eye and head is a not yet fully understood feature of perception. To understand the mechanisms that update the internal coordinates of space, research has mostly focused on eye movements. However, in natural vision, head movements are an integral part of gaze shifts that enlarge the field of vision. Here, we directly compared spatial updating for eye and head movements. In a virtual reality environment, participants had to localize the position of a stimulus across the execution of a gaze shift. We found that performing head movements increased the accuracy of spatial localization. By manipulating the speed of the visual scene displacement that a head movement produced, we found that spatial updating takes into account the sensorimotor contingencies of vision. When we presented gaze-contingent visual motion, subjects overestimated the position of stimuli presented across gaze shifts. The overestimation decreased if subjects were allowed to perform eye movements during the head movement. We conclude that head movements contribute to stabilizing visual space across gaze shifts and that contingencies of head movements, rather than being cancelled, facilitate the updating.
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Background: Children with cerebral palsy often have weak ankle muscles and reduced ankle dorsiflexion, which leads to activity limitations and eventually affects quality of life. Robotic ankle training was recently developed to facilitates muscle function through a high repetition of exercises. This study investigated the effect of six-week ankle training using the Anklebot device to improve lower limb structural and functional impairments and the resulting impact on quality of life. Methods: Five children with spastic cerebral palsy aged between 4 and 11 years participated in six weeks of bilateral ankle assistive training using the Anklebot device. All lower limb muscle strength was measured with a hand-held dynameter, and range of motion was measured with a goniometer, at four different time points. Muscle architecture was assessed using a portable diagnostic ultrasound device, and quality of life was assessed using the Life Habits for Children scale, at two points in time only. Results: Muscle strength and range of motion for all lower limb joints demonstrated significant improvement on both sides after training. The ankle muscle architecture showed non-significant improvement, while an overall significant improvement in the total score of the Life Habits for Children scale was detected after training. Conclusion: Robot-assisted task-specific ankle training provides promising effects by allowing the required repetition to improve structural and functional muscle and joint impairments, which has a positive influence on the children's quality of life. However, due to a limited sample size, these results should be considered as preliminary; further study is needed.
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BACKGROUND: The prediction of postoperative recurrence and survival in cervical cancer patients has been a major clinical challenge. The combination of clinical parameters, inflammatory markers, intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI), and MRI-derived radiomics is expected to support the prediction of recurrence-free survival (RFS), disease-free survival (DFS), tumor-specific survival (CSS), and overall survival (OS) of cervical cancer patients after surgery. METHODS: A retrospective analysis of 181 cervical cancer patients with continuous follow-up was completed. The parameters of IVIM-DWI and radiomics were measured, analyzed, and screened. The LASSO regularization was used to calculate the radiomics score (Rad-score). Multivariate Cox regression analysis was used to construct nomogram models for predicting postoperative RFS, DFS, CSS, and OS in cervical cancer patients, with internal and external validation. RESULTS: Clinical stage, parametrial infiltration, internal irradiation, D-value, and Rad-score were independent prognostic factors for RFS; Squamous cell carcinoma antigen, internal irradiation, D-value, f-value and Rad-score were independent prognostic factors for DFS; Maximum tumor diameter, lymph node metastasis, platelets, D-value and Rad-score were independent prognostic factors for CSS; Lymph node metastasis, systemic inflammation response index, D-value and Rad-score were independent prognostic factors for OS. The AUCs of each model predicting RFS, DFS, CSS, and OS at 1, 3, and 5 years were 0.985, 0.929, 0.910 and 0.833, 0.818, 0.816 and 0.832, 0.863, 0.891 and 0.804, 0.812, 0.870, respectively. CONCLUSIONS: Nomograms based on clinical and imaging parameters showed high clinical value in predicting postoperative RFS, DFS, CSS, and OS of cervical cancer patients and can be used as prognostic markers.
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The human foot is a complex structure comprising 26 bones, whose coordinated movements facilitate proper deformation of the foot, ensuring stable and efficient locomotion. Despite their critical role, the kinematics of foot bones during movement remain largely unexplored, primarily due to the absence of non-invasive methods for measuring foot bone kinematics. This study addresses this gap by proposing a neural network model for estimating foot bone movements using surface markers. To establish a mapping between the positions and orientations of the foot bones and 41 skin markers attached on the human foot, computed tomography scans of the foot with the markers were obtained with eleven healthy adults and thirteen cadaver specimens in different foot postures. The neural network architecture comprises four layers, with input and output layers containing the 41 marker positions and the positions and orientations of the nine foot bones, respectively. The mean errors between estimated and true foot bone position and orientation were 0.5 mm and 0.6 degrees, respectively, indicating that the neural network can provide 3D kinematics of the foot bones with sufficient accuracy in a non-invasive manner, thereby contributing to a better understanding of foot function and the pathogenetic mechanisms underlying foot disorders.
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The limited sample size in gait studies has hampered progress in the field. This challenge could be addressed through multicenter studies, thereby leveraging data sets from different laboratories. This study compared 3-dimensional lower-extremity running kinematics between the Biomechanics and Motor Control Laboratory, Federal University of ABC (Brazil), and the Running Injury Clinic, University of Calgary (Canada). Three-dimensional lower-extremity kinematics from 23 male runners were collected from each laboratory using comparable instrumentation and experimental procedures. The 3-dimensional hip, knee, and ankle angles were compared within and between centers using root-mean-square deviation. Two-sample t tests Statistical Parametric Mapping tested the hypothesis that the data from both laboratories were not different. The sagittal plane hip, knee, and ankle angles were similar between laboratories, while notable differences were observed for frontal (hip and ankle) and transverse (hip and knee) plane angles. The average interlaboratory root-mean-square deviation (2.6°) was lower than the intralaboratory root-mean-square deviation (Biomechanics and Motor Control = 4.8°, Running Injury Clinic = 5.6°), with the ankle transverse angle displaying the smallest, and the knee transverse angle displaying the largest variability. This study demonstrates the potential of combining gait kinematics data from different laboratories to increase sample size, but frontal and transverse plane data should be considered with caution.