Search Results (368)

This paper is aimed to address the issue of decreased accuracy in the ship block docking caused by the structural errors of posture adjustment mechanism. First, inverse kinematic analysis is performed to investigate the sources of static errors in the mechanism. Subsequently, based on the closed-loop vector method, a pose error model for the moving platform is established, which includes eight categories of error terms. The impact of various structural errors on the pose accuracy of the moving platform is then compared and analyzed under both single-limb and multi-limb configurations. Therefore, a compensation method based on the whale optimization algorithm optimized radial basis function neural network is proposed. By transforming pose errors into actuator length errors, it establishes a predictive model between the theoretical pose of the dynamic platform and actuator length errors. After optimizing the network parameters, it yields the actuator length compensation to correct the actual pose of the dynamic platform. Simulation and experimental results validate the effectiveness of this method in enhancing the motion accuracy of the parallel mechanism. The mean pose accuracy of the moving platform is improved by 85.07%, demonstrating a significant compensation effect. Full article

The purpose of this study was to examine the impact of a sensorimotor training program on maximum ankle dorsiflexion (ankle DF), coordination, dynamic balance and postural control, and lower-limb muscle power, in competitive junior surfers, and its relation to parameters of sensorimotor control required to perform aerial maneuvers. Twelve junior competitive surfers followed a 7-week sensorimotor training program, being assessed pre- and post-program with the knee-to-wall test (KW), Y-Balance test—lower quarter (YBT-LQ), and the countermovement jump test (CMJ). Post-training assessment revealed positive effects on the KW (ankle DF) distance, which increased approximately 2 cm (p < 0.001) for both ankles, and all scores for the YTB-LQ (coordination, dynamic balance, and postural control) variables increased, being significant (p < 0.005) for some reach distances (YBT-LQ—Anterior Left, YBT-LQ—Postero-medial Left, and YTB-LQ Anterior Right). YBT-LQ Anterior Reach Asymmetry also improved by decreasing 1.62 cm (p < 0.001) and the CMJ height (lower limb muscle power) increased 2.89 cm (p < 0.001). The training program proved to effectively enhance parameters of physical performance for this sample, including ankle DF, coordination, dynamic balance, postural control, and lower limb muscle power. This tailored-made task approach can help to optimize surfing performance capabilities and contribute to reducing the risk of injuries while performing aerials. Full article

Inappropriate kitchen cooking height may lead to uncomfortable and muscle fatigue. This study aims to compare the effects of kitchen cooking height on upper limb muscle activation, posture, and perceived discomfort among different age groups. Fifteen older women and fifteen young Chinese women each completed three consecutive 20 s simulated cooking tasks at five different heights. Surface electromyography, motion capture, and Borg CR10 scale were used to measure muscle loading. Results showed that the main power muscles of the cooking task were the anterior deltoid, brachioradialis, and biceps brachii. The higher muscle contribution rate of biceps brachii and triceps brachii was found in the younger group compared to the older group (p < 0.05). Muscle activation of the anterior deltoid (different in 1.28–2.87%), pectoralis major (different in 1.43–1.69%), and erector spinae (different in 0.6–1.21%), as well as right shoulder abduction (different in 5.91°–7.96°), were significantly higher in older group than in young group (p < 0.05). Muscle activation of the anterior deltoid and right shoulder abduction decreased significantly with decreasing height (p < 0.05). A height of 200–250 mm below the elbow was considered a more comfortable cooking height for both age groups. This provides data to support the design of cabinet sizes. Full article

Upper and lower limb rehabilitation training is essential for restoring patients’ physical movement ability and enhancing muscle strength and coordination. However, traditional rehabilitation training methods have limitations, such as high costs, low patient participation, and lack of real-time feedback. The purpose of this study is to design and implement a rehabilitation training evaluation system based on virtual reality to improve the quality of patients’ rehabilitation training. This paper proposes an upper and lower limb rehabilitation training evaluation system based on virtual reality technology, aiming to solve the problems existing in traditional rehabilitation training. The system provides patients with an immersive and interactive rehabilitation training environment through virtual reality technology, aiming to improve patients’ participation and rehabilitation effects. This study used Kinect 2.0 and Leap Motion sensors to capture patients’ motion data and transmit them to virtual training scenes. The system designed multiple virtual scenes specifically for different upper and lower limbs, with a focus on hand function training. Through these scenes, patients can perform various movement training, and the system will provide real-time feedback based on the accuracy of the patient’s movements. The experimental results show that patients using the system show higher participation and better rehabilitation training effects. Compared with patients receiving traditional rehabilitation training, patients using the virtual reality system have significantly improved movement accuracy and training participation. The virtual reality rehabilitation training evaluation system developed in this study improves the quality of patients’ rehabilitation and provides personalized treatment information to medical personnel through data collection and analysis, promoting the systematization and personalization of rehabilitation training. This system is innovative and has broad application potential in the field of rehabilitation medicine. Full article

Background/Objectives: Breast cancer-related lymphedema (BCRL) is a chronic condition that has early diagnosis as a critical component for proper treatment. Thermography, a non-invasive imaging method, is considered a promising complementary tool for the diagnosis and monitoring of BCRL, especially in subclinical stages. The present study aimed to evaluate the intra- and inter-examiner reproducibility of thermography for measuring the skin temperature of the upper limbs (UL) of women with and without BCRL. Methods: This study, conducted with women who underwent a unilateral mastectomy, assessed BCRL using indirect volumetry. Maximum, minimum, and mean skin temperatures were measured in five regions of interest (ROI) of each UL (C1, C2, C3, C4, and Cup) in four different postures. Reproducibility measures were assessed using an intraclass correlation coefficient, 95% confidence interval, and coefficient of variation. Results: The sample comprised 30 women; 14 were diagnosed with BCRL. A total of 120 thermograms were recorded in different postures, and 3600 ROI were analyzed in the UL with and without BRCL. The intraclass correlation coefficient of the analyses indicated intra- and inter-examiner reproducibility from good to excellent (0.82 to 1.00) for all skin temperatures evaluated (maximum, minimum, and mean). The coefficient of variation for all measures was below 10%, indicating low variability. Conclusions: Our findings demonstrate that thermography shows good-to-excellent reproducibility across multiple postures and regions of interest, reinforcing its potential as a non-invasive and reliable method for assessing lymphedema in breast cancer survivors. This study establishes a foundation for incorporating thermography into clinical practice for early BCRL detection, particularly in subclinical stages, thus improving patient management and outcomes. Full article

Ankle fractures can lead to issues such as limited dorsiflexion, strength deficits, swelling, stiffness, balance disorders, and functional limitations, which complicate daily activities. This study aimed to describe neuromuscular adaptations at 6 and 12 months post-surgery during static and dynamic balance tasks, specifically using the Y-Balance Test (YBT). Additionally, the relationship between neuromuscular patterns, balance, and musculoskeletal deficits was evaluated. In 21 participants (14 at 6 months and 21 at 12 months) with bimalleolar fractures, hip strength, ankle dorsiflexion, ankle functionality, and static and dynamic balance were assessed using electromyography of five lower limb muscles (tibialis anterior, peroneus longus, lateral gastrocnemius, biceps femoris, and gluteus medius). A significant interaction effect (limb × proximal [hip]—distal [ankle] muscle) (F = 30.806, p < 0.001) was observed in the anterior direction of the Y-Balance Test (YBT_A) at 6 months post-surgery. During the YBT_A and YBT posteromedial (YBT_PM), it was found that a lower dorsiflexion range of movement was associated specifically at 6 months with greater activation of the lateral gastrocnemius. However, these differences tended to diminish by 12 months. These findings suggest that neuromuscular patterns differ between operated and non-operated limbs during the YBT_A at 6 months post-surgery. The Y-Balance Test, particularly its anterior direction, effectively highlighted these neuromuscular changes. This is a preliminary study; further research is needed to explore these findings in depth. Full article

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. Full article

Background/Objectives: This study investigated the behavior of postural adjustments throughout the entire action: from the preparatory phase (anticipatory postural adjustment, APA), the focal movement phase (online postural adjustments, OPA), to the compensatory phase (compensatory postural adjustment, CPA) while raising the arms in a standing position, both with eyes opened and closed. The goal was to analyze the effects of reduced sensorial information and different heights on postural muscle activity during these three phases. Methods: Eight young women performed rapid shoulder flexion while standing on the ground and on a 1-m elevated platform. The EMG activity of the trunk and lower limb muscles was recorded during all three phases. Results: Although average muscle activity was similar on the ground and the elevated platform, the pattern of postural muscle activation varied across the motor action. During OPA, all postural muscle activity was the highest, while it was the lowest during APA. On the elevated platform postural muscles have increased their activation during APA. In the most stable condition (standing on the ground with eyes opened), muscle activity showed a negative correlation between APA and OPA, but there was no correlation between OPA and CPA. Conclusions: Our results suggest postural control adapts to sensory, motor, and cognitive conditions. Therefore, the increased demand for postural control due to the height of the support base demands greater flexibility in postural synergies and alters muscle activity. Full article

Background: Children with developmental coordination disorder (DCD) exhibit reduced interlimb coordination compared to typically developing children (TDC) during complex tasks like running, which requires dynamic postural control. However, the extent of interlimb coordination difficulties in DCD during tasks that demand minimal dynamic balance, such as self-paced and externally auditory-paced tasks, remains unclear. This study aimed to compare interlimb coordination and auditory–motor synchronization between children with DCD and TDC during a seated antiphase coordination task of the lower limbs, which has minimal postural control requirements. Methods: Twenty-one children with DCD and 22 TDC performed an antiphase knee flexion and extension task while seated, in three conditions (baseline silence, metronome discrete, and metronome continuous), for three minutes. The interlimb coordination, synchronization, and spatiotemporal movement parameters were analyzed using a mixed model analysis; Results: Children with DCD displayed less coordinated interlimb movements compared to TDC (p = 0.0140), which was the result of the greater variability in coordinating antiphase knee flexion–extension movements (p < 0.0001). No group differences in spatiotemporal movement parameters were observed. Children with DCD, compared to TDC, had a lower synchronization consistency to metronomes (p = 0.0155). Discrete metronomes enhanced interlimb coordination compared to the baseline silence condition (p = 0.0046); Conclusions: The study highlights an inferior interlimb coordination and auditory–motor synchronization in children with DCD compared to TDC. Implementing metronomes with a discrete temporal structure improved the interlimb coordination of both groups during the used fundamental seated interlimb coordination task, supporting theorical frameworks of event-based timing. Full article

Background/Objectives: The flexibility deficits of hip flexors have been identified as potential biomechanical risk factors for the lumbo–pelvic–hip complex, with postural repercussions on the trunk and lower limbs. The purpose of this study was to conduct a single gravity stretching experiment and to monitor its acute and prolonged effects. Methods: The sample comprised 14 healthy participants (8 females and 6 males). Data were collected during two-day measurement sessions. These analyzed via Kinovea software. The single intervention (i.e., gravity stretching) was performed on the first day. A modified Thomas test was used at the same time in two ways, both as a measurement and as an intervention tool. Stretching was achieved by relaxing in a position to perform the modified Thomas test where, each participant lies completely relaxed for 3 min, allowing gravity to stretch the hip flexors of the examined limb. Results: After intervention, a significant acute increase in hip extension range of motion and a decrease in knee extension range of motion were found. We did not find any significant prolonged effects; moreover, after 48 h, the hip range of motion almost returned to the initial value. Conclusions: A single 3 min stretch is very effective in terms of achieving immediate changes in the range of motion, but insufficient for long-term improvements in flexibility. Full article

In recent years, Romania’s stomatology private practice sector has seen substantial growth, with many dentists fully committing to building and expanding their own practices, often funded by their personal income. This study aimed to explore how various postures affect the muscle groups of dentists (380), particularly focusing on identifying positions that may jeopardize their musculoskeletal health. A group of dentists effectively participated in this study (10), adhering to their regular work routines while wearing wearable sensors on their backs to monitor posture and activity. The data gathered from these sensors were analyzed using the RULA (rapid upper-limb assessment) and REBA (rapid entire-body assessment) tools. The findings indicated that the head and shoulder movements during dental procedures involved considerable and repetitive angular shifts, which could strain the neck and back muscles and heighten the risk of musculoskeletal problems. Additionally, the standing postures adopted by the dentists were associated with an increased risk of postural issues and greater overall fatigue. Extended periods of trunk and head tilting were also identified as contributing factors to posture-related challenges. Full article

Background and Objectives: The aim of this study was to assess postural stability in patients after total and unicompartmental knee arthroplasties. Materials and Methods: The study included 40 women who had undergone knee arthroplasties—20 women who had undergone total knee arthroplasty (TKA) (mean age 63.47 ± 2.17) and 20 women who had undergone unicompartmental knee arthroplasty (UKA) (mean age 64.65 ± 1.93). The comparison group consisted of 20 healthy women aged 60–69 years (mean age 64.45 ± 3.12). The average time from surgery to stabilometry was 14.4 months. Each patient underwent stabilography using a single-plate stabilography platform, which included both Romberg’s test and a dynamic test. Additionally, the WOMAC scale was administered, where patients assessed their condition both before surgery and at the present time. Results: The averaged Romberg’s test results show a slight displacement in the center of mass (COM) toward the forefoot and towards the right limb in both the TKA and UKA groups. The WOMAC scale results showed significant improvement and satisfactory functional outcomes in both groups. Conclusions: The study indicated that one year after surgery, patients in both groups required a larger base of support to maintain postural control. However, the results for the UKA group were more similar to those of healthy individuals. Full article

The purpose of this study is to investigate the effect of task constraints on the neurobiological systems while maintaining postural control under various sensory feedback manipulations in individuals with and without Chronic Ankle Instability (CAI). Forty-two physically active individuals, with and without CAI, were enrolled in a case-control study conducted at a biomechanics research laboratory. All participants underwent the Sensory Organization Test (SOT), which assesses individuals’ ability to integrate somatosensory, visual, and vestibular feedback to maintain postural control in double-, uninjured-, and injured-limb stances under six different conditions in which variations in the sway-referenced support surface (platform) and visual surroundings, with and without vision, are manipulated to affect somatosensory and visual feedback. Center-of-Pressure (COP) path length was computed from raw data collected during trials of each SOT condition. Sample Entropy (SampEN) values were extracted from the COP path length time series to examine neurobiological systems complexity, with lower SampEN values indicating more predictable and periodic (rigid) neurobiological systems, while higher SampEN values indicate more unpredictable and random systems. The results show that specific task constraints affect the neurobiological systems. Specifically, individuals with CAI demonstrated reduced complexity (decreased SampEN values) in the neurobiological systems during the uninjured-limb stance when all sensory feedback was intact and during both uninjured- and injured-limb stances when they were forced to rely on vestibular feedback. These results highlight the interplay between sensory feedback and task constraints in individuals with CAI and suggest potential adaptations in the neurobiological systems involved in postural control. Full article

Background/Objectives: Inappropriate posture, overweight, and physical inactivity are common causes of pathologies on muscles, ligaments, joints, and bone structures, which could negatively impact the quality of present and future life. The challenge of this work was to develop a diagnostic approach to identify the causes of musculoskeletal disorders in an adolescent population in order to implement preventive procedures. Methods: A total of 147 subjects aged between 14 and 18 years who were affected by musculoskeletal disorders and who accessed the Clinical Posturology unit of the IRCCS San Gerardo hospital, Monza, Italy, from 2015 to 2023, were enrolled. The clinical evaluation of each subject included a posturology visit, a physical examination, instrumental devices, such as stabilometric platform, gait analysis, MuscleLab, and imaging tests, such as Radiographic and Magnetic resonance, and a final diagnosis. Results: Ninety-eight (66.6%) subjects reported pain at the lumbar spine (33.3%), followed by knee/lower limb (22.4%), cervical spine (13%), and dorsal spine (12.3%). Imaging diagnostics underlined alterations in the musculoskeletal components, bone dimorphism, and asymmetry of the skeleton in 68% of cases. Thirty-one (21%) subjects received a diagnosis of postural dysfunction, seventy-two (49%) received a diagnosis of somatic dysfunction, and ten (7%) received a diagnosis of both postural and somatic dysfunctions. Conclusions: Our work highlighted that the three instrumental devices used allowed us to detect somatic and postural functional changes that cause musculoskeletal pathologies in adolescents. Full article

Background: This study evaluated the effectiveness of radio electric asymmetric conveyer (REAC) neurobiological optimization treatments on muscle strength (MS) in individuals with post-polio syndrome (PPS), a condition causing new muscle weakness in polio survivors. Traditional treatments focus on symptom management, whereas REAC technology uses radio electric symmetric conveyed fields to modulate neurotransmission and cellular function. Methods: This open-label study involved 17 PPS patients who maintained their existing medications. The participants underwent four REAC treatment protocols: neuro-postural optimization (NPO), neuro-psycho-physical optimization (NPPO), neuro-psycho-physical optimization—cervical brachial (NPPO-CB), and neuromuscular optimization (NMO). MS was assessed using manual muscular tests (MMT) before and after each protocol. Results: A statistical analysis via repeated measures ANOVA showed significant MS improvements, particularly in the proximal muscles of the left lower limb (LLL), distal muscles of both lower limbs (LLs), and distal muscles of the left upper limb. The LLL, the most severely affected limb at this study’s start, exhibited the greatest improvement. Conclusions: These results suggest REAC treatments could enhance MS in PPS patients, potentially reorganizing motor patterns and reducing functional overload on less affected limbs. Full article