Search Results (110)

The spinal angle is an important indicator of body balance. It is important to restore the 3D shape of the human body and estimate the spine center line. Existing multi-image-based body restoration methods require expensive equipment and complex procedures, and single image-based body restoration methods struggle to accurately estimate internal structures such as the spine center line due to occlusion and viewpoint limitation. This study proposes a method to compensate for the shortcomings of the multi-image-based method and to overcome the limitations of the single-image method. We propose a 3D body posture analysis system that integrates depth images from four directions to restore a 3D human model and automatically estimate the spine center line. Through hierarchical matching of global and fine registration, restoration to noise and occlusion is performed. In addition, adaptive vertex reduction is applied to maintain the resolution and shape reliability of the mesh, and the accuracy and stability of spinal angle estimation are simultaneously secured using the level of detail (LOD) ensemble. The proposed method achieves high-precision 3D spine registration estimation without relying on training data or complex neural network models, and the verification confirms the improvement in matching quality. Full article

Background: Neuromuscular electrical stimulation (NMES) is an effective exogenous neuromuscular activation method widely used in sports training and rehabilitation. However, existing research primarily focuses on land-based sports or single-joint movements, with limited in-depth exploration of its intervention effects and underlying neuromuscular control mechanisms for complex, multi-joint coordinated aquatic activities like breaststroke swimming. This study aimed to investigate the effects of NMES combined with traditional resistance training on neuromuscular function during sport-specific technical movements in breaststroke athletes. Methods: A randomized controlled trial was conducted with 30 national-level or above breaststroke athletes assigned to either an experimental group (NMES combined with traditional squat resistance training) or a control group (traditional squat resistance training only) for an 8-week intervention. A specialized fully waterproof wireless electromyography (EMG) sensor system (Mini Wave Infinity Waterproof) was used to synchronously collect surface EMG signals from 10 lower limb and trunk muscles during actual swimming, combined with high-speed video for movement phase segmentation. Changes in lower limb explosive power were assessed using a force plate. Non-negative matrix factorization (NMF) muscle synergy analysis was employed to compare changes in muscle activation levels (iEMG, RMS) and synergy patterns (spatial structure, temporal activation coefficients) across different phases of the breaststroke kick before and after the intervention. Results: Compared to the control group, the experimental group demonstrated significantly greater improvements in single-leg jump height (Δ = 0.06 m vs. 0.03 m) and double-leg jump height (Δ = 0.07 m vs. 0.03 m). Time-domain EMG analysis revealed that the experimental group showed more significant increases in iEMG values for the adductor longus, adductor magnus, and gastrocnemius lateralis during the leg-retraction and leg-flipping phases (p < 0.05). During the pedal-clamp phase, the experimental group exhibited significantly reduced activation of the tibialis anterior alongside enhanced activation of the gastrocnemius. Muscle synergy analysis indicated that post-intervention, the experimental group showed a significant increase in the weighting of the vastus medialis and biceps femoris within synergy module 4 (SYN4, related to propulsion and posture) (p < 0.05), a significant increase in rectus abdominis weighting within synergy module 3 (SYN3, p = 0.033), and a significant shortening of the activation duration of synergy module 2 (SYN2, p = 0.007). Conclusions: NMES combined with traditional resistance training significantly enhances land-based explosive power in breaststroke athletes and specifically optimizes neuromuscular control strategies during the underwater breaststroke kick. This optimization is characterized by improved activation efficiency of key muscle groups, more economical coordination of antagonist muscles, and adaptive remodeling of inter-muscle synergy patterns in specific movement phases. This study provides novel evidence supporting the application of NMES in swimming-specific strength training, spanning from macroscopic performance to microscopic neural control. Full article

To address the complex surface curvature, massive dimensions, and variable pitch angles of wind turbine blades, this paper proposes a climbing robot design based on a variable-cell mechanism. By dynamically adjusting the support span and body posture, the robot adapts to the geometric features of different blade regions, enabling stable and efficient non-destructive inspection operations. Two reconfigurable configurations—a planar quadrilateral and a regular hexagon—are proposed based on the geometric characteristics of different blade regions. The configuration switching conditions and multi-leg cooperative control mechanisms are investigated. Through static stability margin analysis, the stable gait space and maximum stride length for each configuration are determined, optimizing the robot’s motion performance on surfaces with varying curvature. Simulation and experimental results demonstrate that the proposed multi-configuration gait planning strategy exhibits excellent adaptability and climbing stability across segments of varying curvature. This provides a theoretical foundation and methodological support for the engineering application of robots in wind turbine blade maintenance. Full article

To address the high incidence of work-related musculoskeletal disorders (WMSDs) at manual edge-banding workstations in furniture factories, and in an effort to tackle the existing research challenges of poor cumulative risk quantification and inconsistent evaluations, this paper proposes a three-stage system for continuous, automated, non-invasive WMSD risk monitoring. First, MediaPipe 0.10.11 is used to extract 33 key joint coordinates, compute seven types of joint angles, and resolve missing joint data, ensuring biomechanical data integrity for subsequent analysis. Second, joint angles are converted into graded parameters via RULA, REBA, and OWAS criteria, enabling automatic calculation of posture risk scores and grades. Third, an Adaptive Pooling Convolutional Neural Network (CNN) and Long Short-Term Memory Network (LSTM) dual-branch hybrid model based on the Efficient Channel Attention (ECA) mechanism is built, which takes nine-dimensional features as the input to predict expert-rated fatigue states. For validation, 32 experienced female workers performed manual edge-banding tasks, with smartphones capturing videos of the eight work steps to ensure authentic and representative data. The results show the following findings: (1) system ratings strongly correlate with expert evaluations, verifying its validity for posture risk assessment; (2) the hybrid model successfully captures the complex mapping of expert-derived fatigue patterns, outperforming standalone CNN and LSTM models in fatigue prediction—by integrating CNN-based spatial feature extraction and LSTM-based temporal analysis—and accurately maps fatigue indexes while generating intervention recommendations. This study addresses the limitations of traditional manual evaluations (e.g., subjectivity, poor temporal resolution, and inability to capture cumulative risk), providing an engineered solution for WMSD prevention at these workstations and serving as a technical reference for occupational health management in labor-intensive industries. Full article

Background: Juvenile Idiopathic Arthritis (JIA) is a chronic inflammatory condition that can disrupt joint function and biomechanics, often leading to altered gait patterns. When coexisting with secondary scoliosis—a common musculoskeletal complication in children with JIA—postural and movement impairments may be further exacerbated. However, limited research has investigated the combined impact of JIA and secondary scoliosis on gait characteristics. This study aimed to evaluate gait parameters in children diagnosed with JIA and secondary scoliosis and to compare them with age-matched healthy peers. Methods: A total of 50 children (25 with JIA and secondary scoliosis, 25 healthy controls) were included. Demographic data, plantar pressure distribution, temporal gait parameters, and center of mass (CoM) displacement were assessed using computerized gait analysis. Group comparisons were performed using appropriate statistical methods. Results: Children with JIA and secondary scoliosis exhibited significantly lower forefoot loading on both dominant and non-dominant sides compared to controls (p < 0.05). Maximum loading values were also reduced bilaterally in the JIA group (p < 0.001). The dominant side single-limb support duration was significantly shorter (p = 0.027), and CoM displacement was greater (p = 0.044) in the JIA group. No differences were observed in rearfoot loading or walking speed. Conclusions: Children with coexisting JIA and secondary scoliosis demonstrate altered gait mechanics, likely reflecting compensatory adaptations due to joint inflammation and postural asymmetries. Gait analysis may offer valuable insights for tailoring rehabilitation strategies in this patient population. Full article

The ergonomic risks associated with posture in conventional office workstations have been extensively studied, but there is limited research available on these risks in the context of home-based work environments. Most available studies rely solely on questionnaire-based statistical analyses, leaving a gap in understanding the specific conditions of home-based work environments. This study focuses on evaluating the effects of workstation conditions on posture and muscular efforts across three anatomical segments: head-neck, trunk-upper trapezius, and arm-deltoid. The analysis is conducted by simulating workstation setups commonly associated with academic activities performed by students during the COVID-19 pandemic. The conditions examined in this study include inadequate desk height, the use of chairs without armrests, and the use of laptops. Eighteen volunteers, comprising nine women and nine men, participated in experiments conducted under scenarios designed using a $2^k$ statistical approach. In all experiments, participants completed questionnaires, and text-writing activities were performed to evaluate the effects of these conditions. This research introduces a new non-invasive technique for ergonomic assessment that integrates photogrammetry and surface electromyography (sEMG) to simultaneously evaluate posture and muscular effort. The developed methodology allows precise, contactless analysis of ergonomic conditions and can be adapted for various professional and academic teleworking environments. Significant effects were observed in the posture (°) of the trunk and head, with both small and large effects identified at significance levels of p < 0.001 under the furniture conditions studied. In terms of EMG activity, moderate effects were observed at p < 0.01 levels between table height and upper trapezius activation, while small effects were detected at p < 0.05 levels between the use of chairs without armrests and neck. Similarly, small to moderate effects were observed in the arm-deltoid segment under the same furniture conditions. These findings reveal information about the posture and muscular effort patterns associated with the studied tasks, offering knowledge that can be referenced for similar tasks in other technical fields where telematics activities are performed. Full article

Repetitive non-concussive head impacts (NCHIs) may contribute to long-term neurodegenerative conditions. However, objective, multimodal methods for monitoring acute changes in brain health biomarkers following NCHIs remain underdeveloped. In this exploratory study, we examined the effects of ten kicking and ten heading trials related to association football on linear and nonlinear measures of postural control and corticospinal inhibition. Postural control was assessed via force platform analysis in dual-stance and single-leg protocols, and corticospinal inhibition was measured using transcranial magnetic stimulation with electromyography. Large effects of condition were found for anteroposterior postural complexity (CI-AP), anteroposterior sway amplitude, mediolateral centre of pressure shift and cortical silent period (η² > 0.14). Pairwise comparisons revealed large post-heading effects, particularly in CI-AP, which decreased significantly relative to baseline (d_z = 0.71, p = 0.018) and showed a moderate negative effect relative to post-kicking testing (d_z = 0.53, p = 0.069). These findings suggest a possible reduction in postural control adaptability following exposure to ten NCHIs, consistent with patterns observed in mild traumatic brain injury. Whilst confirmatory research with larger samples is warranted, nonlinear measures of postural control complexity demonstrate promise as a sensitive biomarker for detecting acute NCHI-related changes. Full article

Background/Objectives: Maintaining postural control is critical for preventing falls, especially in older adults, yet traditional center-of-pressure (COP) analyses may not capture subtle age-related balance impairments. In this study, we integrated a dynamic posturographic assessment—the Tiptoe Rising Test—with an innovative Trend Change Index (TCI) analysis, a method adapted from stock market technical indicators, to enhance the sensitivity of balance evaluations. Methods: Twenty-four healthy older adults (65+ years) and twenty healthy young adults (18–30 years) completed both the Limits of Stability (LOS) test and the Tiptoe Rising Test. During each assessment, COP data were continuously recorded via a force plate, and both conventional COP parameters (e.g., sway range, velocity, standard deviation) and dynamic TCI metrics (including TCI_dT, TCI_dS, TCI_dV, and TCI_per_s) were computed. Results: Our results indicate that while the LOS test showed limited group differences using standard COP measures—particularly during less dynamic phases—the TCI-derived indices revealed moderate to large effect sizes in capturing temporal and spatial fluctuations in postural adjustments. Notably, the Tiptoe Rising Test, with its inherently dynamic challenge, produced robust differences between young and older participants, with TCI metrics consistently demonstrating enhanced sensitivity in detecting subtle balance impairments. Conclusions: These findings suggest that incorporating TCI analysis with dynamic balance tasks, such as the Tiptoe Rising Test, provides a more comprehensive and discriminative assessment of postural control. This integrated approach holds promise for early detection of balance deficits and may inform targeted interventions aimed at fall prevention in the elderly population. Full article

Chronic low back pain (cLBP) is a pervasive and debilitating condition that can result in motor control deficits and often leads to opioid dependence. Conventional rehabilitation approaches generally rely on internally driven tasks, which fail to capture adaptive motor responses to external perturbations. This study focuses on the design and evaluation of a pneumatic-actuated active balance board integrating pneumatic artificial muscles (PAMs), electromyography (EMG), and inertial measurement units (IMUs) to assess seated postural control responses. With PAM-powered perturbations, the balance board introduces controlled challenges to evaluate postural control dynamics and motor adaptation. EMG sensors monitor muscle activity in key postural muscles, while IMU systems track movement responses. The system was evaluated through an experimental trial with 15 healthy participants performing balance tasks on both a passive and active balance board. The active balance board’s effectiveness is assessed using signal processing techniques, including root mean square (RMS) analysis, Fast Fourier Transform (FFT), autoregressive (AR) modeling, and the Welch t-test. Experimental trials were conducted with healthy participants to establish baseline performance. Results demonstrate that the active balance board successfully induces adaptive motor responses, with higher EMG activation levels compared to passive boards. Frequency-domain analyses confirm significant differences in muscle activation patterns, supporting the hypothesis that external perturbations enhance postural control retraining. The pneumatic-actuated balance board presented in this study represents a novel approach to postural control assessment that may be applied in future rehabilitation studies involving individuals with cLBP, addressing the limitations of traditional methods. Future research will focus on clinical trials with cLBP patients to further evaluate its therapeutic efficacy and long-term benefits in rehabilitation. Full article

Background/Objectives: In the elderly population, thoracic kyphosis often progresses with age, leading to secondary postural adaptations including scapular protraction, internal rotation, and anterior tilt. These alterations can potentially compromise shoulder biomechanics, particularly in patients undergoing reverse shoulder arthroplasty (RSA). The purpose of this study was to evaluate the relationship between thoracic sagittal alignment, quantified by the Cobb angle, and scapular internal rotation (SIR) assessed on CT scans in patients scheduled for RSA. Methods: A retrospective study was conducted on 164 patients who underwent RSA between 2016 and 2024 at a single tertiary referral center. Sagittal thoracic kyphosis was assessed using the Cobb angle measured on preoperative chest radiographs. SIR and anterior scapular tilt were evaluated using preoperative CT scans. Patients were divided into three groups according to the Cobb angle: Group A (≤36°), Group B (>36–46°), and Group C (≥47°). Statistical analysis was performed using the Spearman correlation coefficient and Kruskal–Wallis test, with a significance threshold set at p < 0.05. Results: Analysis demonstrated a weak but statistically significant positive correlation between age and SIR, as well as between thoracic kyphosis (Cobb angle) and SIR. Patients in Group C (Cobb angle ≥ 47°) showed higher mean SIR values (43.7°) compared to Group A (40.3°), with statistical significance achieved (p = 0.047). These findings suggest that greater thoracic kyphosis is associated with increased scapular internal rotation. No significant correlation was identified between anterior scapular tilt and thoracic kyphosis. Conclusions: This study reveals a correlation between increased thoracic kyphosis and greater scapular internal rotation in patients undergoing RSA. These postural and biomechanical alterations may have critical implications for surgical planning and postoperative outcomes. Preoperative assessment of sagittal spinal alignment, particularly thoracic kyphosis, should be integrated into the planning process for RSA to optimize implant positioning and improve functional results. Full article

Background/Objectives: Non-invasive methods for evaluating rehabilitation outcomes in Parkinson’s disease (PD) remain limited. This preliminary study proposes a mechanics-informed machine learning (ML) framework integrating force-plate data with dimensionality reduction, clustering, and statistical analysis to objectively assess motor control and the effects of a targeted intervention. Methods: Twelve PD patients were randomly assigned to a PD control group performing standard exercises or an intervention group incorporating additional transverse-plane trunk motion exercises for 10 weeks. Ground reaction forces and center of pressure (COP) signals were recorded pre- and post-intervention using a force plate, alongside data from six healthy individuals as a benchmark. Features related to postural sway and COP dynamics were extracted and refined using Forward Feature Selection. Dimensionality reduction (t-SNE) and unsupervised clustering (K-means) identified group-level patterns. SHAP values and Cohen’s d quantified feature importance and effect size. Clustering robustness was assessed with bootstrapping, nested cross-validation, and permutation testing. Results: K-means clustering revealed clear pre/post-intervention separation in five of six intervention patients, with post-intervention states shifting toward the control cluster. Clustering showed strong performance (Silhouette 0.77–0.79; Calinski–Harabasz 100.8–184.9; Davies–Bouldin 0.29–0.45). The most predictive features (RMS-SML and PL-SAP) showed large effect sizes (Cohen’s d = –12.1 and –4.53, respectively) distinguishing PD patients from healthy controls. Traditional statistical tests (e.g., ANOVA) failed to detect within-group changes (p > 0.05), but ML-based methods captured subtle, nonlinear postural adaptations. Conclusions: This preliminary mechanics-informed ML framework detects PD-related motor deficits and rehabilitation-induced improvements using force-plate data, warranting validation in larger cohorts. Full article

Background/Objectives: This study aimed to conduct the cross-cultural adaptation and assess the reliability of a validated measurement instrument, the Back-Health Related Postural Habits in Daily Activities (BEHALVES). Methods: Following a standardized methodological framework for the cross-cultural adaptation of health-related instruments, the BEHALVES questionnaire was translated and tested in 104 primary education students (mean age 13.8 ± 0.74 years; 49.1% girls) at two different time points with a 1-week interval between each test. The analysis was expressed as test–retest reliability according to the differences observed between the readings (T1–T2, α = Cronbach’s alpha), the standard deviation of the differences (SD), the intraclass correlation coefficient (ICC), 95% confidence intervals for the intraclass correlation coefficient, standard error of measurement (SEM), coefficient of repeatability (CR), and minimal detectable change (MDC). Results: Internal consistency results for the joint analysis of items grouped into categories were good (α = 0.72). Lying down was the worst-performing category in this study. The ICC was excellent for the total score (0.96) and all categories (0.90–0.99). Regression analysis between the mean of the two measures and their difference indicated that there was a significant difference (F1,103 = 0.19, p < 0.001; beta coefficient = −0.15, p < 0.001; R2 = 0.16). Conclusions: The BEHALVES questionnaire is valid and reliable for the Polish youth population, providing similar results to the original Spanish version. The continued development of reliable measurement instruments will enhance research in education, public health, and clinical practice, ultimately leading to improved strategies for preventing postural issues in young populations. Full article

To address the challenges in concrete vibration during the construction of concrete-faced rockfill dams, this study proposes a multi-objective-driven lightweight and high-frequency vibrating robotic arm (VRA). The proposed system aims to improve adaptability and performance under harsh site conditions, such as inclined slab surfaces and confined rebar layouts. Based on the geometric structure and task characteristics of the VRA, a multi-objective topology optimization framework was established, integrating compromise programming and average frequency strategies. This method simultaneously achieves mass reduction, stiffness enhancement, and modal frequency improvement to avoid resonance during high-frequency operations. The workspace of the VRA was verified using kinematic modeling and Monte Carlo sampling, and a critical physical posture—where the arm is fully extended horizontally, producing maximum span and joint loads—was identified to extract dynamic load boundaries. Finite element analysis was then conducted under worst-case conditions, and the optimization results were validated by modal analysis and flexibility metrics. The optimized VRA demonstrated substantial improvements in structural performance, reducing overall mass, lowering flexibility, and increasing modal frequencies. The proposed framework provides a transferable approach for designing high-frequency robotic arms in vibration-intensive scenarios, supporting intelligent construction in concrete-faced rockfill dams and similar complex environments. Full article

This narrative review addresses the complexities of managing the vertical dimension of occlusion (VDO) in restorative dentistry, focusing on predictability in prosthetic reconstructions. Altering VDO impacts biological, biomechanical, esthetic, and functional aspects, making it a controversial topic. While VDO naturally evolves throughout life, interventions require careful consideration due to potential complications. Various techniques guide VDO determination, including facial proportions, physiological methods, phonetics, and cephalometric analysis. Clinicians must understand these principles and adapt them to individual patient needs. Materials and Methods: A narrative literature review was conducted using PubMed, Scopus, Google Scholar, and the Cochrane Library, searching keywords like “vertical dimension of occlusion”, “dental”, “diagnosis”, “management” and “complications”. In addition to the literature review, two case reports with extensive prosthodontic restorations were included to illustrate the diagnostic challenges and treatment considerations in a clinical setting. Results: Increasing VDO aids restorative treatments, re-establishing morphology, and facilitating additive procedures. Minimally invasive approaches, provisional restorations, and fixed restorations with functional contours are favored. Individualized, patient-centered care is critical, recognizing unique anatomical and functional needs. This approach optimizes stomatognathic system rehabilitation while preventing adverse effects on body posture and airway dimensions. Conclusions: To ensure predictable results and minimize risks, changes in VDO should be kept to a minimum to achieve dentofacial aesthetic harmony and secure adequate space for the planned restorations The two case reports presented, with different clinical approaches, underline the importance of understanding the potential risks and benefits of VDO alteration which is crucial for achieving predictable and successful outcomes in complex restorative cases. Full article

The mental and emotional health of an athlete is crucial for their performance and well-being. Sports-related stress can significantly impair their mental health. Further, there were minimal tools available to measure Sports resilience, specifically during COVID-19 restrictions or earlier. This study reports the preliminary validation of the Sports Mind Inventory (SMI) in athletes from different geographical areas (n = 66), with the majority of participants from Mauritius, and tests the SMI in elite athletes practicing the Yoga of Immortals (YOI). YOI is a unique combination of specific yogic postures, breathing exercises, sound therapy & meditation, which has demonstrated benefit in improving measures of mental health. The exploratory factor analysis of the 24-item SMI resulted in a six-factor inventory. The confirmatory factor analysis of these six-factor SMI showed goodness-of-fit index (0.935), and Cronbach’s alpha coefficient (α) of 0.949, showing good fit and reliability. The correlation between overall scale and individual factors showed diverse degree of positive correlations. This validated SMI was then tested to investigate whether YOI can enhance athletes’ resilience to sports-related stress. Participants were a diverse set of athletes based in Mauritius who routinely engage in a wide range of athletic activities. Participants were randomly assigned to receive four weeks of YOI or no intervention. Both groups completed the SMI questionnaire at baseline and again after four weeks. The YOI intervention significantly increased (p = 0.002) the total mean SMI scores, and underlying factors, i.e., Factor 1: Positive and Competitive sports mindset (p = 0.014), Factor 2: Social relatedness and adaptability (p = 0.008), Factor 3: Resilient mindset and self-confidence (p = 0.036), Factor 4: Sports Resilience and Emotional Responses (p = 0.001). This indicated improved sports resilience and psychological health. No improvement was observed in the control group. The correlation analysis in YOI group at week-4 showed positive correlation between overall scales and underlying construct. In conclusion, SMI showed acceptable fitness to measure sport resilience. This YOI intervention helped in improving sports-related stress and improved athletes’ resilience. Full article