Motion Analysis Research Articles

Continuum Mechanics Applied to the Biomechanics of Motion.

Continuum Mechanics is the discipline that studies the motion and deformation of material bodies, and is at the basis of both Solid Mechanics and Fluid Mechanics. This works aims at highlighting how a basic education in modern Continuum Mechanics can be of fundamental importance not only in the Biomechanics of Tissue, but also in the Biomechanics of Movement. The latter is largely based on Rigid Body Mechanics, which can be considered as a simple particular case of the general theory of Continuum Mechanics. As an example, a straightforward methodology for the extraction of the angular velocity from motion analysis data is illustrated. The method is based on a quantity that is more primitive than the angular velocity: the spin tensor.

Relationship between the flexion relaxation phenomenon and kinematics of the multi-segmental spine in nonspecific chronic low back pain patients

The flexion relaxation phenomenon (FRP) is characterized by the reduction of paraspinal muscle activity at maximum trunk flexion. FRP is reported to be altered (persistence of spinal muscle activity) in more than half of nonspecific chronic low back pain (NSCLBP) patients. Little is known about how the multi-segmental spine affects FRP. The aim of this observational study was to investigate the relationship between FRP and kinematic parameters of the multi-segmental spine in NSCLBP patients. Forty NSCLBP patients and thirty-five asymptomatic participants performed a standing maximal trunk flexion task. Surface electromyography was recorded along the erector spinae longissimus. The kinematics of the spine were assessed using a 3D motion analysis system. The investigated spinal segments were upper thoracic, lower thoracic, thoracolumbar, upper lumbar, lower lumbar, and lumbopelvic. Upper lumbar ROM, anterior sagittal inclination of the upper lumbar relative to the lower lumbar in the upright position, and ROM of the upper lumbar relative to the lower lumbar during full trunk flexion were significantly correlated with the flexion relaxation ratio (Rho 0.42 to 0.58, p < 0.006). The relative position and movement of the upper lumbar segment seem to play an important role in the presence or absence of FRP in NSCLBP patients.

Study on a Novel Reseeding Device of a Precision Potato Planter

In order to address the problem of a high miss-seeding rate in mechanized potato planting work, a novel reseeding device is designed and analyzed. Based on dynamic and kinematic principles, the seed potato’s motion analysis model in the seed preparation process was constructed. The analysis results indicate that the seed preparation performance is positively related to the seed preparation opening length l1 and inclination angle of the seed-returning pipe θ. Then, the potato’s motion analysis model in the reseeding process was constructed. The analysis showed that the displacement of seeding potatoes in the horizontal direction ds is influenced by the initial seeding potato’s speed , dropping height hs, and the angle between the seeding pipe and the horizontal ground βs. The horizontal moving distance xr of the reseeding potatoes is influenced by the angle between the bottom of the reseeding pipe and horizontal ground βs2, the distance from its centroid to the reseeding door d, and the dropping height of the potato hr. The analysis results indicated that the reseeding potato can be effectively discharged into the furrow. Then, a prototype of a reseeding control system was constructed based on the STM32 microcontroller, electric pushers, and through-beam laser sensors. The simulation analysis was conducted to verify the theoretical analysis by using EDEM2020 software. The simulation results indicated that with the increase in the seeding chain speed, the seed preparation success rate initially increased slowly and then decreased gradually. The seed preparation performance can be increased by increasing the seed preparation opening length or decreasing the seed-returning pipe inclination angle. The impact on the successful seed preparation rate is ranked by significance as follows: seed preparation opening length &gt; seed-returning pipe inclination angle &gt; chain speed. Then, the prototype reseeding device and the corresponding seed metering device were manufactured and a series of bench tests and field tests were conducted. The bench test results showed an average successful seed preparation rate of 93.6%. The average qualified-seeding rate, miss-seeding rate, and multi-seeding rate in the field test were 89.6%, 2.46%, and 7.94%, respectively. This study can provide a theoretical reference for the design of potato reseeding devices.

Estimation of Lower Limb Joint Angles Using sEMG Signals and RGB-D Camera.

Estimating human joint angles is a crucial task in motion analysis, gesture recognition, and motion intention prediction. This paper presents a novel model-based approach for generating reliable and accurate human joint angle estimation using a dual-branch network. The proposed network leverages combined features derived from encoded sEMG signals and RGB-D image data. To ensure the accuracy and reliability of the estimation algorithm, the proposed network employs a convolutional autoencoder to generate a high-level compression of sEMG features aimed at motion prediction. Considering the variability in the distribution of sEMG signals, the proposed network introduces a vision-based joint regression network to maintain the stability of combined features. Taking into account latency, occlusion, and shading issues with vision data acquisition, the feature fusion network utilizes high-frequency sEMG features as weights for specific features extracted from image data. The proposed method achieves effective human body joint angle estimation for motion analysis and motion intention prediction by mitigating the effects of non-stationary sEMG signals.

Modified tai chi movement training based on sEMG and movement analysis on improving upper extremities motor function: a protocol for a clinical randomised controlled trial

IntroductionStroke survivors often face motor dysfunction, increasing fall risk. Lower extremity muscle weakness is a key factor affecting walking ability. Tai chi (TC) has been shown to improve muscle strength...

Digital workflow in oral splint manufacturing.

The objective of the present article is to demonstrate the digital workflow used to manufacture an adjusted oral splint in a patient case. A 25-year-old female patient presented for management of her bruxism. Therefore, an adjusted oral splint was manufactured. A computer-aided motion analysis of the patient was conducted (JMA Optic). Full-arch scans of the maxilla and mandible, a biocopy of the maxilla with a bite fork, and buccal scans of the centric jaw relation (Primescan) were performed. The jaw relation was determined beforehand by ballistic closing on a chairside-fabricated anterior jig. The digital construction of a Michigan splint took place in the dental laboratory. The design was nested and milled from a polymethyl methacrylate (PMMA)-containing blank (CLEARsplint Disc). The oral splint was inserted into the patient's mouth and checked to ensure a tension-free fit. The static and dynamic contact relationship was checked. During the follow-up visit, the patient reported an improvement in tension in the masticatory muscles. The described procedure allows for the manufacture of an adjusted oral splint through a purely digital workflow.

Kinematic calibration of a 5-DOF double-driven parallel mechanism with sub-closed loop on limbs

Abstract This paper proposes a kinematic calibration method of a novel 5-degree-of-freedom double-driven parallel mechanism with the sub-closed loop on limbs. At first, considering the introduction of a sub-closed loop significantly increased the complexity and difficulty of kinematic error modeling, an equivalent transformation method is proposed for the limb with a sub-closed loop. Then kinematic error model of the parallel mechanism is established based on the closed-loop vector method and parasitic motion analysis, which is verified by virtual prototype technology. Because the full kinematic error model is generally redundant, error parameter identifiability analysis is carried out by QR decomposition of the identification Jacobian matrix, and the redundant parameters are removed. Additionally, the Sequence Forward Floating Search algorithm is utilized to optimize measurement configurations to reduce the influence of measurement noise. Finally, with a laser tracker as the measuring device, numerical simulations and experiments are implemented to verify the proposed kinematic calibration method. The experiment results show that average position and orientation errors are reduced from 2.778 mm and 1.115° to 0.263 mm and 0.176°, respectively, within the prescribed workspace.

Existence of Tracking Brownian Nanoparticle Technique with Reducing its First Collision Time with One of the Nanosensors in the Interactive Medium

This study discusses the existence of tracking N-dimensional Brownian nanoparticle in an interactive medium, where this tracking is based on Brownian motion analysis. A group of N nanosensors begin the tracking process at the origin of N dimensional space, where the nanosensors serve an important role in detecting and monitoring this nanoparticle. Each nanosensor oscillates as it passes through the origin of its planer surface (to the right and left) in the presence of a succession of random points on each axis. The space's plans cross on a real line, with the origin (0,0,...,0). Because of this uncertainty, we may be able to calculate the overall distance in each tracking step as a function of a discounted effort-reward parameter. We show analytically how this parameter influences demonstrating the existence of this model and lowering the computationally expected value of the first collision time between a nanosensor and a nanoparticle.

Enhanced Infant Movement Analysis Using Transformer-Based Fusion of Diverse Video Features for Neurodevelopmental Monitoring

Neurodevelopment is a highly intricate process, and early detection of abnormalities is critical for optimizing outcomes through timely intervention. Accurate and cost-effective diagnostic methods for neurological disorders, particularly in infants, remain a significant challenge due to the heterogeneity of data and the variability in neurodevelopmental conditions. This study recruited twelve parent–infant pairs, with infants aged 3 to 12 months. Approximately 25 min of 2D video footage was captured, documenting natural play interactions between the infants and toys. We developed a novel, open-source method to classify and analyse infant movement patterns using deep learning techniques, specifically employing a transformer-based fusion model that integrates multiple video features within a unified deep neural network. This approach significantly outperforms traditional methods reliant on individual video features, achieving an accuracy of over 90%. Furthermore, a sensitivity analysis revealed that the pose estimation contributed far less to the model’s output than the pre-trained transformer and convolutional neural network (CNN) components, providing key insights into the relative importance of different feature sets. By providing a more robust, accurate and low-cost analysis of movement patterns, our work aims to enhance the early detection and potential prediction of neurodevelopmental delays, whilst providing insight into the functioning of the transformer-based fusion models of diverse video features.

Anterior and coracoid base tunnel location combined with single -or double clavicular tunnel techniques using double-button fixation for coracoclavicular ligament reconstruction both restore horizontal stability. A biomechanical cadaver study

BackgroundThe placement of clavicle tunnels in coracoclavicular ligament reconstruction is well established, but the optimal position of the coracoid tunnel remains unclear. This study aimed to investigate how the coracoid tunnel's position affects horizontal stability during coracoclavicular ligament reconstruction using a double-button technique. MethodsFifteen fresh frozen shoulder cadaver specimens were tested under various conditions: intact coracoclavicular ligaments, disrupted ligaments, and reconstructions with a single coracoid and clavicle tunnel or double clavicle tunnels. The coracoid tunnel was positioned at the coracoid base 1/9, and 1/5 anterior to the base. Specimens underwent displacement-controlled loading, with 2D motion analysis conducted on captured digital images using TEMA motion analysis. FindingsMean displacement for intact coracoclavicular ligaments was 1.61 ± 0.92 mm, and 3.69 ± 1.09 mm for disrupted ligaments. For reconstructed conditions, displacements were as follows: Single-Tunnel Base (1.87 ± 0.64 mm), Single-Tunnel 1/9 (2.54 ± 1.13 mm), Single-Tunnel 1/5 (2.62 ± 1.17 mm), Double-Tunnel Base (1.25 ± 0.73 mm), Double-Tunnel 1/9 (2.03 ± 1.22 mm), and Double-Tunnel 1/5 (1.88 ± 1.20 mm). Differences among intact, reconstructed, and disrupted states were statistically significant (p = 0.01–0.0001), with all reconstruction techniques restoring horizontal displacement near the intact state. InterpretationAt point zero both single coracoid tunnel and single- and double-clavicle tunnel restored horizontal displacement to its intact state. Coracoid tunnel placement anterior to the base of the coracoid did not influence horizontal displacement but single coracoid at the coracoid base and single clavicle tunnel resulted in the most anatomic reconstruction. Single coracoid tunnel at the base and double-clavicle resulted in the most stable reconstruction.

AI Applications in Adult Stroke Recovery and Rehabilitation: A Scoping Review Using AI

Stroke is a leading cause of long-term disability worldwide. With the advancements in sensor technologies and data availability, artificial intelligence (AI) holds the promise of improving the amount, quality and efficiency of care and enhancing the precision of stroke rehabilitation. We aimed to identify and characterize the existing research on AI applications in stroke recovery and rehabilitation of adults, including categories of application and progression of technologies over time. Data were collected from peer-reviewed articles across various electronic databases up to January 2024. Insights were extracted using AI-enhanced multi-method, data-driven techniques, including clustering of themes and topics. This scoping review summarizes outcomes from 704 studies. Four common themes (impairment, assisted intervention, prediction and imaging, and neuroscience) were identified, in which time-linked patterns emerged. The impairment theme revealed a focus on motor function, gait and mobility, while the assisted intervention theme included applications of robotic and brain–computer interface (BCI) techniques. AI applications progressed over time, starting from conceptualization and then expanding to a broader range of techniques in supervised learning, artificial neural networks (ANN), natural language processing (NLP) and more. Applications focused on upper limb rehabilitation were reviewed in more detail, with machine learning (ML), deep learning techniques and sensors such as inertial measurement units (IMU) used for upper limb and functional movement analysis. AI applications have potential to facilitate tailored therapeutic delivery, thereby contributing to the optimization of rehabilitation outcomes and promoting sustained recovery from rehabilitation to real-world settings.

Effect of Cognitive Decline on Mandibular Movement during Mastication in Nursing Home Residents.

Background: Many studies have reported on the relationship between cognitive and masticatory functions. However, it remains unclear how the mandibular movements change during chewing in facility residents as dementia progresses. This study aimed to investigate the relationship between a kinematic analysis of mandibular movement during mastication and cognitive function in facility residents. Methods: Sixty-three participants were included from two long-term care facilities. The primary outcome variable was the kinematic data of mandibular movement during mastication. The participants chewed rice crackers, and their faces were recorded during this motion. The partial correlation coefficient between kinematic data and cognitive function was calculated. Furthermore, group comparisons were performed after dividing the participants into three groups based on their cognitive function. Results: Circular motion frequency was significantly correlated with the ABC dementia scale, even after adjusting for the appendicular skeletal muscle index, Eichner index, and short-form mini-nutritional assessment. The cycle and circular motion frequencies were markedly lower in the severe dementia group than in the mild dementia group. Conclusions: With declining cognitive function, mandibular movements during mastication decrease in circular motion and increase in linear motion. Additionally, our results suggested that residents with severe cognitive impairment had more linear mandibular motions during mastication than those with mild cognitive impairment. This may make it more difficult for residents with cognitive decline to ingest normal solid foods.

Recent evaluation and analysis of the clinical effect of two closed treatment methods in children with intracapsular condyle fracture

Objective: To summarize and analyze clinical characteristics of pediatric mandibular condylar fractures and the long-term therapeutic effects of closed treatment. Methods: A retrospective study was conducted for pediatric condylar fracture in the Department of Oral and Maxillofacial Surgery of Peking University School and Hospital of Stomatology from October 2015 to October 2019, including 33 males (67.3%) and 16 females (32.7%), with an average age of (8.3±2.1) years old. According to the treatment methods, the children were divided into two groups: group A was a removable occlusal splint accompanied with functional exercise, group B was a pure functional exercise. Forty-nine cases (76 sides) children with intracapsular condylar fracture were included in this study. Twenty-three cases in group A and 26 cases in group B. The maximum month opening increased from (20.0±6.2) mm to (46.0±5.3) mm 6 months after closed treatment. Subjective evaluation, special examination, qualitative analysis and quantitative analysis of imaging were used to evaluate the condylar remodeling and functional recovery of temporomandibular joint in two groups of children after closed treatment of intracapsular condyle fracture. Results: There was no significant difference in subjective evaluation, maximum opening examination, mouth open-type, mandibular protrusion, lateral movement and qualitative analysis of imaging at the six-month follow-up after injury. Quantitative imaging measurements showed that the condylar anteroposterior diameter and condylar height in Group B were significantly higher than those in Group A after 1 year of injury. Conclusions: Closed treatment for pediatric condylar fractures can achieve satisfactory results. After 6 months of injury, the children in the two groups could recover the temporomandibular joint function and promote the condylar adaptative remodeling.

SAW-driven directional clearance of bacteria on submerged surfaces

The process of bacterial film formation on submerged surfaces commences with the attachment of bacteria to the substrate. Appropriate combinations of topology and surface chemistry have been explored to prevent biofilm anchoring at the solid–liquid interface. However, the failure to actively remove bacteria from solid surfaces within a fluid in a directional manner results in bacterial backflow onto those surfaces, thus leading to secondary contaminations. Herein, inspired by the biology broom of the ciliary beating system, we propose an active surface sweeper mechanism assisted by charged particles and surface acoustic waves (SAW) to facilitate the directional clearance of bacteria. Through the synergistic effect of charge trapping and acoustic propelling, the sweeper system demonstrates an effective inhibition of bacterial adhesion in the initial stage of biofilm formation. Utilizing SAW for twenty seconds yields a remarkable 94.8% efficiency in bacterial clearance, with antibacterial adhesion efficiency up to 92.4% and 98.8% for Escherichia coli and Staphylococcus aureus, respectively. Moreover, the accompanying theoretical force modeling offers a comprehensive mechanistic insight into the relationship between acoustic streaming and bacteria repelling. The motion analysis of bacteria-loaded particles suggests that the acoustic radiation force, rather than the Strokes force, determines the clearance direction of bacteria.

Kinematics of elongate harvestmen chelicerae: Comparative range of motion analyses in extant Ischyropsalis (Dyspnoi, Opiliones)

Chelicerae, the mouthparts of chelicerates, are essential for food processing. Particularly within harvestmen (Opiliones), some species have greatly elongated their tripartite chelicerae and utilize them for mating behavior, defense, and primarily for predation. We investigated two European species, Ischyropsalis muellneri and Ischyropsalis hellwigii, which occupy different niches (caves, forests), exhibit different feeding ecologies (opportunist, specialist), and first and foremost possess different chelicerae morphologies (long and thin, short and robust). We scanned the specimens using state-of-the-art micro-CT, generated surface reconstructions, and equipped one chelicera of each specimen with artificial joints to explore their Range of Motion in a 3D kinematic approach. For a size-corrected comparison of the two species, we analyzed the Range of Motion in addition to three different settings (original body size, body scaled to 5 mm, chelicerae scaled to 5 mm). Ischyropsalis muellneri reached a higher maximum excursion angle (= single Range of Motion) in all three joints, also exhibiting a greater total Range of Motion in the original body length setting, as well as the scaled body length setting. Only in the third setting, the total Range of Motion of Ischyropsalis hellwigii was slightly higher, although Ischyropsalis muellneri still extended further ventrally. Our results suggest that the sturdier, more massive chelicerae of Ischyropsalis hellwigii, attributable to strong specialization on snails as prey, are associated with reduced Range of Motion. The less food-specialized species Ischyropsalis muellneri apparently requires higher flexibility of its chelicerae for prey capture, likely due to its restriction to cave ecosystems, where food availability is relatively scarce. We could show that virtual Range of Motion analyses in harvestmen chelicerae can play a pivotal role in understanding the theoretical feeding ecology and functional morphology of this group. This approach can be verified by in-vivo observations and measurements or extended to other arachnid taxa and other body parts.

Towards Automatic Object Detection and Activity Recognition in Indoor Climbing

Rock climbing has propelled from niche sport to mainstream free-time activity and Olympic sport. Moreover, climbing can be studied as an example of a high-stakes perception-action task. However, understanding what constitutes an expert climber is not simple or straightforward. As a dynamic and high-risk activity, climbing requires a precise interplay between cognition, perception, and precise action execution. While prior research has predominantly focused on the movement aspect of climbing (i.e., skeletal posture and individual limb movements), recent studies have also examined the climber’s visual attention and its links to their performance. To associate the climber’s attention with their actions, however, has traditionally required frame-by-frame manual coding of the recorded eye-tracking videos. To overcome this challenge and automatically contextualize the analysis of eye movements in indoor climbing, we present deep learning-driven (YOLOv5) hold detection that facilitates automatic grasp recognition. To demonstrate the framework, we examined the expert climber’s eye movements and egocentric perspective acquired from eye-tracking glasses (SMI and Tobii Glasses 2). Using the framework, we observed that the expert climber’s grasping duration was positively correlated with total fixation duration (r = 0.807) and fixation count (r = 0.864); however, it was negatively correlated with the fixation rate (r = −0.402) and saccade rate (r = −0.344). The findings indicate the moments of cognitive processing and visual search that occurred during decision making and route prospecting. Our work contributes to research on eye–body performance and coordination in high-stakes contexts, and informs the sport science and expands the applications, e.g., in training optimization, injury prevention, and coaching.

Analysis of fabric movement and dust removal performance due to twist motion in a clothing care system

This study aims to explore effective dust removal methods for the improvement of clothing care systems by analyzing the fabric movement caused by the twist motion and examining its influence on dust removal performance. The finite element method simulation was used to model the tension at different vertical and horizontal positions of the fabric as a spring array, to calculate the fabric movements at each position over time when a twisting force was applied and enable comparison with experiments. When observing the fabric movement due to the twist motion with actual fabrics, silk showed the greatest movement, followed by cotton and linen. Cotton experienced decreasing force from the top to the bottom, with increased amplitude at the bottom due to fluttering caused by the bottom not being fixed. When examining the fabric movement according to the velocity, slower velocity did not effectively transmit twist force to the bottom, while faster velocity resulted in more small movements. The analysis revealed that greater force at faster velocity led to better dust removal performance. Therefore, for efficient dust removal, the force transmitted to the fabric should be increased. Most dust is removed within the first 10 min, so exerting a strong force for a short duration is important.

Viscoelasticity estimation of sports prosthesis by energy-minimizing inverse kinematics and its validation by forward dynamics

In this study, we present a method for estimating the viscoelasticity of a leaf-spring sports prosthesis using advanced energy minimizing inverse kinematics based on the Piece-wise Constant Strain (PCS) model to reconstruct the three-dimensional dynamic behavior. Dynamic motion analysis of the athlete and prosthesis is important to clarify the effect of prosthesis characteristics on foot function. However, three-dimensional deformation calculations of the prosthesis and viscoelasticity have rarely been investigated. In this letter, we apply the PCS model to a prosthesis deformation, which can calculate flexible deformation with low computational cost and handle kinematics and dynamics. In addition, we propose an inverse kinematics calculation method that is consistent with the material properties of the prosthesis by considering the minimization of elastic energy. Furthermore, we propose a method to estimate the viscoelasticity by solving a quadratic programming based on the measured motion capture data. The calculated strains are more reasonable than the results obtained by conventional inverse kinematics calculation. From the result of the viscoelasticity estimation, we simulate the prosthetic motion by forward dynamics calculation and confirm that this result corresponds to the measured motion. These results indicate that our approach adequately models the dynamic phenomena, including the viscoelasticity of the prosthesis.

Effect of Unanticipated Tasks on Side-Cutting Stability of Lower Extremity with Patellofemoral Pain Syndrome.

Patellofemoral pain syndrome (PFPS) is one of the most common causes of anterior knee pain encountered in the outpatient setting. The purpose of this study was to compare the lower limb biomechanical differences during anticipated and unanticipated side-cutting in athletes with PFPS. Fifteen male basketball players diagnosed with PFPS were enrolled in the study. Participants executed both anticipated and unanticipated 45-degree side-cutting tasks. Motion analysis systems, force plates, and electromyography (EMG) were used to assess the lower limb joint angles, joint moments, joint stiffness, and patellofemoral joint contact forces. Analyzed biomechanical data were used to compare the differences between the two circumstances. Unanticipated side-cutting resulted in significantly increased ankle plantarflexion and dorsiflexion angles, knee abduction and internal rotation angles, and hip abduction angles, as well as heightened knee adduction moments. Additionally, patellofemoral joint contact forces and stress increased, while contact area decreased during unanticipated tasks. Unanticipated movement raises the demands for joint stability and neuromuscular control, increasing injury risks in athletes with PFPS. These findings have practical implications for developing targeted rehabilitation programs and injury prevention strategies.

UWB distance estimation errors in (non-)line of sight situations within the context of 3D analysis of human movement

Abstract Integrated Ultrawideband (UWB) and Magnetic Inertial Measurement Unit (MIMU) sensors are becoming popular for indoor localization applications, as a higher accuracy can be achieved than with just MIMU sensors. These integrated sensors could extend stability and accuracy in the field of 3D analysis of human movement (3D AHM) if they can deliver position estimates with an accuracy close to 1 cm. Achieving this high accuracy of 1 cm remains challenging, with most studies reporting position estimation errors around 5 cm, often due to Non-Line of Sight (NLOS) conditions and systematic UWB sensor distance estimation errors. Studying the distance error characteristic of UWB in situations of 3D AHM is essential to deal with these errors. While research on UWB distance errors in Line of Sight (LOS) and NLOS situations exists, few studies focus on the NLOS errors caused by the human body and were not in the relevant scenarios of 3D AHM. Therefore, this article examines UWB sensor performance and distance error characteristics in LOS and NLOS situations typical for the 3D AHM. Both the LOS and NLOS situations were studied in the typical 3D AHM distance range of 0.2 m to 2 m. The NLOS situations were studied first with a human subject as NLOS causing object and then with simulated human body segments (PVC pipes filled with water) of varying diameters. In LOS situations, consistent systematic bias errors were observed, along with incidental errors at specific positions in the room. In NLOS scenarios caused by the human and simulated body segments, a consistent and reproducible overestimation of distances was found. The reproducibility of these errors based on relative node and object positions suggests that systematic mitigation methods could significantly reduce errors, enabling more accurate and reproducible 3D human movement analysis.