During transfer tasks, the dual-arm nursing-care robot require a human-robot mechanics model to determine the balance region to support the patient safely and stably. Previous studies utilized human-robot two-dimensional static equilibrium models, ignoring the human body volume and muscle torques, which decreased model accuracy and confined the robot ability to adjust the patient's posture in three-dimensional spatial. Therefore, this study proposes a three-dimensional spatial mechanics modeling method based on individualized human musculoskeletal multibody dynamics. Firstly, based on the mechanical features of dual-arm support, this study constructed a foundational three-dimensional human-robot mechanics model including body posture, contact position and body force. With the computed tomography data from subjects, a three-dimensional femur-pelvis-sacrum model was reconstructed, and the individualized musculoskeletal dynamics was analyzed using the ergonomics software, which derived the human joint forces and completed the mechanic model. Then, this study established a dual-arm robot transfer platform to conduct subject transfer experiments, showing that the constructed mechanics model possessed higher accuracy than previous methods. In summary, this study provides a three-dimensional human-robot mechanics model adapting to individual transfers, which has potential application in various scenarios such as nursing-care and rehabilitating robots.
Humans ; Robotics ; Biomechanical Phenomena ; Posture ; Imaging, Three-Dimensional ; Nursing Care

Objective:To investigate the effects of the Epley and Semont procedures with varying lateral angles of the head on posterior semicircular canal benign paroxysmal positional vertigo （PC-BPPV）. Methods:A total of 115 patients with unilateral PC-BPPV were randomly divided into five groups: Epley group, Semont group, Semont+10° group, Semont+20° group, and Semont+30° group, with 23 patients in each group. Corresponding reduction treatments were performed. Results:The total effective rates for the Epley group, Semont group, Semont+10° group, Semont+20° group, and Semont+30° group were 95.7% （22/23）, 4.3% （1/23）, 30.4% （7/23）, 52.2% （12/23）, and 87.0% （20/23） respectively. The inefficiencies were 4.3% （1/23）, 95.7% （22/23）, 69.6% （16/23）, 47.8% （11/23）, and 13.0% （3/23）. Statistically significant differences were observed in the total effective rates among the five groups （χ²=54.11, P<0.01）. The total effective rates in the Semont group, Semont+10° group, and Semont+20° group were significantly different from that of the Epley group （P<0.01）, while no statistically significant difference was found between the Semont+30° group and the Epley group （P= 0.608>0.012 5）. Conclusion:Among the four Semont methods with different lateral lying angles, the total effective rate of reduction treatment increased with the elevation of the lateral lying angle on the affected side. The efficacy of the Semont+30° group in treating PC-BPPV was not significantly different from the Epley group's reduction effect, which was markedly superior to that of the other four Semont methods at different angles. Therefore, the Semont+30° reduction technique is recommended for the treatment of PC-BPPV.
Adult ; Aged ; Female ; Humans ; Male ; Middle Aged ; Benign Paroxysmal Positional Vertigo/therapy* ; Head ; Posture ; Semicircular Canals/physiopathology* ; Treatment Outcome

Sit-to-stand is an indispensable functional activity in human daily life, which requires high muscle strength, not only to control the lower limbs, but also to ensure the stable ascension of the trunk. This paper describes in detail the trajectory and speed of the joints through the human sit-to-stand test, analyzes the change rule of the angle of the joints, the angular velocity and the position of the center of mass in the human sit-to-stand, and records in detail the change of the plantar pressure of the subjects in this process. Through the study on joint motion and plantar pressure changes in the process of sit-to-stand, this paper summarizes the kinematics of human body in this process, aiming to provide a basis through the results of this paper for the design of human sit-to-stand assistive devices, which may be used in the future to analyze the sit-to-stand state of patients with lower limb disorders, and carry out the corresponding treatment and rehabilitation training.
Humans ; Biomechanical Phenomena ; Foot/physiology* ; Pressure ; Standing Position ; Adult ; Posture/physiology* ; Movement/physiology* ; Sitting Position

Aging is a crucial factor influencing postural stability control and contributing to frequent falls, yet its underlying mechanisms remain incompletely understood. This study aims to explore the effects of aging on postural stability control by comparing differences in postural stability and node strength of electroencephalogram (EEG) brain network between elderly and young people under the conditions of congruent and incongruent visual-vestibular sensory inputs. Eighteen elderly volunteers without neuromuscular disorders and eighteen young individuals participated in the present study. Virtual reality (VR) technology was employed to manipulate visual rotation stimuli (clockwise and counterclockwise), and a horizontal rotating platform was used for vestibular rotation stimuli (clockwise). Based on the directional disparity of sensory input in the horizontal plane, visual-vestibular input consistency was categorized as congruent and incongruent. Postural stability was assessed by the center of pressure (COP) trajectory, and EEG signals were collected and analyzed using directed network analysis to observe EEG brain network node connectivity strength. The results revealed that, under conditions of incongruent visual-vestibular sensory inputs, the elderly exhibited significantly inferior postural stability performance in terms of COP anterior-posterior (Y-axial) sway speed, total path length, anterior-posterior and medial-lateral sample entropy, compared to the young adults. Moreover, the node connectivity strength of visual cortex in the elderly was notably higher, while node connectivity strength of superior temporal cortex was significantly lower than that in the young adults. These findings suggest that the elderly have a heightened reliance on visual information in postural control and an impaired ability to cope with sensory conflicts arising from incongruent visual-vestibular sensory inputs, leading to compromised postural stability. The outcomes of this study hold significant implications for future assessments of balance function in the elder and fall prevention trainings.
Young Adult ; Humans ; Aged ; Adolescent ; Posture ; Postural Balance ; Aging ; Brain

In view of the high incidence of malignant diseases such as malignant arrhythmias in the elderly population, accidental injuries such as falls, and the problem of no witnesses when danger occurs, the study developed a human vital signs and body posture monitoring and positioning alarm system. Through the collection and analysis of electrocardiogram (ECG), respiration (RESP) and acceleration (ACC) signals, the system monitors human vital signs and body posture in real time, automatically judges critical states such as malignant arrhythmias and accidental falls on the local device side, and then issues alarm information, opens the positioning function, and uploads physiological information and patient location information through 4G communication. Experiments have shown that the system can accurately determine the occurrence of ventricular fibrillation and falls, and issue position and alarm information.
Humans ; Aged ; Arrhythmias, Cardiac/diagnosis* ; Ventricular Fibrillation ; Electrocardiography ; Accidental Falls ; Vital Signs ; Posture ; Monitoring, Physiologic

OBJECTIVE: To investigate the effect of different postures on direct anterior approach(DAA) total hip arthroplasty. METHODS: Total of 94 patients who underwent DAA total hip arthroplasty from July 2016 to June 2020 were retrospectively analyzed. They were divided into two groups according to different positions during the operation, including 45 cases in lateral position and 49 cases in supine position (with the aid of stent). The general data such as gender, affected limb, body mass index(BMI), incision length, operation time, intraoperative bleeding volume, drainage volume 24 hours after operation, hemoglobin difference before and after operation, first landing time after operation, postoperative hospitalization time, postoperative complications, visual analogue scale(VAS) at 1 day, 1, 2 weeks, 1, 3 and 6 months after operation, Harris score at 1, 2 weeks, 1, 3 and 6 months after operation were observed and compared between the two groups. RESULTS: Patients in both groups were followed up for 6 to 12 months with an average of (8.31±2.22) months. There was no significant difference between two groups in gender, affected limb, age, height, weight, body mass index(BMI), preoperative VAS score and preoperative Harris score(P>0.05). The incision length, operation time, intraoperative bleeding volume, 24-hour drainage volume, hemoglobin difference before and after operation, first time to the ground and postoperative hospitalization time of patients in supine position (assisted by stent) group were all better than those in lateral position group(P<0.05);There was no significant difference in the number of blood transfusions during and after operation(P=0.550). There was no significant difference in anteversion angle and abduction angle in the supine position(with the aid of stent) group during and after operation (P=0.825, P=0.066);There was significant difference in anteversion angle and abduction angle in the lateral position group during and after operation(P<0.05). VAS of patients in supine position (assisted by stent) group were lower than those in lateral position group at 1 day, 1, 2 weeks and 1 month after operation(P<0.05), and there was no statistical difference between two groups at 3 and 6 months after operation(P>0.05). Harris scores of patients in supine position(assisted by stent) group were higher than those in lateral position group at 1 week, 1 month and 3 months after operation(P<0.05), and there was no significant difference between two groups at 6 months after operation(P>0.05). CONCLUSION Compared with the lateral position, the supine position DAA total hip arthroplasty has the advantages of small incision, short operation time, less bleeding, early landing time, short hospitalization time, and small intraoperative acetabular cup position judgment error. It has the advantage of fast postoperative recovery, but the recovery of hip joint function is the same after 6 months.
Humans ; Arthroplasty, Replacement, Hip ; Retrospective Studies ; Antiviral Agents ; Treatment Outcome ; Posture

INTRODUCTION: Due to COVID-19 pandemic, many have shifted into working at home which led to physical inactivity. This may cause musculoskeletal discomfort, chronic disease, muscle atrophy and spinal imbalance due to improper and prolonged sitting posture. Since mobile devices are relatively available for most of the office workers, there were still a lack of evidence-based mobile applications that can counteract the inactivity through exercises, which led to the researchers to create an application called SitMate that consists of evidence-based exercises which aimed to prevent musculoskeletal discomfort among a business process outsourcing company Workforce Management Personnel (BPO-WMP). METHODS: Eleven participants (18-40 years old) full-time, work-from-home BPO-WMP were randomized into Treatment Group(TG)(n=6) and Control Group (CG)(n=5). The TG received one month intervention with the use of SitMate Application containing relaxation exercises, range of motion exercises and stretching exercises, and notifications for postural correction while the CG continued their usual working schedule. RESULTS: There were no significant differences between two groups on all body parts that were measured using the Cornell Musculoskeletal Discomfort Questionnaire, and no significant differences in the intragroup pre-test and post-test scores on all body parts between TG and CG. For the intra-group post-test of the TG, there were noted improvements on the hip/buttock, right shoulder, upper back (median = 0) and right wrist (median = 1.5). There was also a noted increase in discomfort on the neck (median = 1.5) and lower back (median = 3). For the post-test of the CG, there were noted improvements on the right shoulder, right wrist (median = 0) and lower back (median = 1.5). CONCLUSION This study has shown that the SitMate application does not effectively reduce the prolonged sitting-related discomfort among the personnel after 1 month of intervention.
mobile application ; musculoskeletal discomfort ; physical inactivity ; low back pain ; posture

Objective: To simulate and evaluate the scraping and grinding work of workers with different spinal anteversion angles, and to explore the effects of different anteversion angles on the erector spinae muscles of scrapers. Methods: In November 2019, 16 male college student volunteers were recruited to simulate workers' scraping and grinding work. The parameters were 25°, 15 times/min, 15°, 30 times/min, 5°, 60 times/min respectively. The surface electromyography (sEMG) was used to collect the electromyographic signals of the erector spinae muscles, and the surface electromyographic characteristics of the erector spinae muscles were evaluated with Borg Scale. Results: There were significant differences between the maximum voluntary contraction percentage (MVE%) of the left and right erector spinae muscles groups in the three groups with different spinal anteversion angles (F(left)=13.41, P(left)<0.001; F(right)=4.74, P(right)=0.005) , and the EMG amplitude was higher at 25°, 15 times/min. At 15°, 30 times/min, MVE% of the left side was significantly higher than that of the right side (t=2.58, P=0.021) . There was significant difference in the mean power frequency (MPF) of the right erector spinae muscle in the three groups (F=9.42, P<0.001) , but there was no significant difference in the MPF of the left erector spinae muscle (F=0.30, P=0.823) . The fitting line showed that the left erector spinae muscle showed a downward trend at 5°, 60 times/min (t=-5.39, P=0.012) . Conclusion: Scrapers are less likely to be fatigued when the posture is 15°, 30 times/min, but they are more likely to be fatigued when working at 5°, 60 times/min.
Electromyography ; Humans ; Male ; Muscle, Skeletal/physiology* ; Muscles/physiology* ; Posture/physiology*

OBJECTIVE: Whether the developed new type of radiotherapy auxiliary fixation device compatible with the head and neck joint coil can improve the quality of magnetic resonance images in radiotherapy and verify whether it can be applied to clinical treatment. METHODS: The clinical trial selected patients with brain metastases and nasopharyngeal cancer patients, using thermoplastic film and head and shoulder molds for posture fixation, and treatment on the ELekta Versa accelerator. SPSS 20.0 statistical software was used to analyze the data. The measurement data were expressed by RESULTS: Considering the influence of the outer contour of the device, the target dose meets the clinical requirements. The setting error is less than 2 mm in the three translation directions, and the rotation error is less than 2 CONCLUSIONS There is no statistical difference between the treatment results of patients using the new type of fixation device and the conventional method. The target area threatens the organ dose, and the positioning error meets the treatment requirements.
Humans ; Magnetic Resonance Imaging ; Magnetic Resonance Spectroscopy ; Nasopharyngeal Neoplasms ; Neck ; Posture

OBJECTIVE: To assess the effects of loupes and microscope on the posture of prosthodontists when preparing the laminate veneer, and to assess the clinical value of loupes and microscope from the ergonomic aspects. METHODS: Twenty young prosthodontists from Department of Prosthodontics, Peking University School and Hospital of Stomatology were recruited into this study, which was a prospective, single blind, self-control trials. The research hypothesis was concealed and the participants were deceived about the precise purpose of the study to counterbalance the lack of direct blinding. The prosthodontists prepared laminate veneers of open window type in the artificial dental model, under routine visual field (control group), 2.5× headwear loupes (loupes group), and 8× operating microscope (microscopic group) by turning. The participants were photographed from profile view and front view. Thereafter, the subjective assessment was performed by themselves using the visual analogue score (VAS). The expert assessment was performed by two professors using modified-dental operator posture assessment instrument on the basis of photographs of the profile view and front view. RESULTS: The subjective assessment scores for the control group, loupes group and microscopic group were 4.55±1.96, 7.90±1.12, and 9.00±0.92, respectively. There was significant difference between the three groups' subjective scores (P < 0.05). The expert assessment scores for the control group, loupes group and microscopic group were 16.38±1.52, 15.15±1.30, and 13.60±0.88, respectively. There was significant difference between the three groups' expert assessment scores (P < 0.05). Specifically, the three groups' expert assessment scores were significantly different (P < 0.05) in trunk position (front to back) (1.33±0.41, 1.03±0.11, 1.00±0.00), head and neck position (front to back) (2.75±0.38, 2.13±0.36, 1.23±0.38), elbows level (1.38±0.43, 1.40±0.45, 1.13±0.22), and shoulders level (1.43±0.41, 1.23±0.34, 1.13±0.28). Thereinto, the microscopic group was better than loupes group in head and neck position (front to back) and elbows level (P < 0.05). CONCLUSION Loupes and microscope improve the posture of the prosthodontist when preparing the laminate veneer, in which the microscope is better than loupes. Therefore, the magnification devices have clinical value from the ergonomic aspects.
Dentists ; Ergonomics ; Humans ; Posture ; Prospective Studies ; Single-Blind Method