Based on the joint analysis of EMG spectrum and amplitude method (JASA), a study on muscle fatigue assessment of spinal surgical instruments based on surface EMG signals was carried out, and a comparative evaluation of the operating comfort before and after the optimization of spinal surgical instruments was completed. A total of 17 subjects were recruited to collect the surface EMG signals of their brachioradialis and biceps. Five surgical instruments before and after optimization were selected for data comparison, and the operating fatigue time proportion of each group of instruments under the same task was calculated based on the RMS and MF eigenvalues. The results showed that when completing the same operation task, the operation fatigue time of the surgical instruments before optimization was significantly higher than that after optimization (P<0.05); there was no significant difference in the fatigue status of brachioradialis and biceps when operating the same instrument (P>0.05). These results provide objective data and reference for the ergonomic design of surgical instruments and fatigue damage protection.
Humans ; Muscle Fatigue/physiology* ; Muscle, Skeletal ; Electromyography ; Ergonomics

Ergonomics ; Humans ; Musculoskeletal Diseases ; Occupational Diseases

Ergonomics ; Humans ; Industry ; Musculoskeletal Diseases/epidemiology* ; Occupational Diseases/epidemiology* ; Risk Factors

Brain-computer interface (BCI) is a revolutionizing human-computer Interaction, which is developing towards the direction of intelligent brain-computer interaction and brain-computer intelligent integration. However, the practical application of BCI is facing great challenges. The maturity of BCI technology has not yet reached the needs of users. The traditional design method of BCI needs to be improved. It is necessary to pay attention to BCI human factors engineering, which plays an important role in narrowing the gap between research and practical application, but it has not attracted enough attention and has not been specifically discussed in depth. Aiming at BCI human factors engineering, this article expounds the design requirements (from users), design ideas, objectives and methods, as well as evaluation indexes of BCI with the human-centred-design. BCI human factors engineering is expected to make BCI system design under different use conditions more in line with human characteristics, abilities and needs, improve the user satisfaction of BCI system, enhance the user experience of BCI system, improve the intelligence of BCI, and make BCI move towards practical application.
Brain ; Brain-Computer Interfaces ; Electroencephalography ; Ergonomics ; Humans ; User-Computer Interface

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

Musculoskeletal Discomfort And Its Associated Risk Factors Among Train Drivers This study was conducted to determine the prevalence and associated risk factors of musculoskeletal disorders among train drivers in Kuala Lumpur. In this cross-sectional study, 44 train drivers were interviewed using a self-administered questionnaire consists of socio-demographic information and occupational exposure; and a modified Nordic Standardised Questionnaire for questions related to musculoskeletal discomfort symptoms. Results showed that lower back (18.6%) are the most reported discomfort among train drivers, followed by neck (16.7%), knee (13.7%), and upper back (13.7%). Statistical analysis using Chi-square showed there is a significant association between discomfort in the neck with age (p<0.05), length of service (p<0.05), and the perception of driver’s seat comfort and suitability (P<0.001). Previous working experience, driving duration, and shift work were associated with shoulder, wrist and thigh discomfort. This study suggested that further investigation and early control measure need to be done to prevent the risk of the musculoskeletal problem among train drivers.
musculoskeletal disorders ; occupational hazards ; ergonomics ; freight ; cargo ; locomotive ; prevalence.

The best commonly applied approach in seating ergonomics is the concept that the seat must fit the sitter.Understanding of population anthropometry is necessary because, in the mass vehicle market, a single seat should fit a huge portion of the population. This research work proposes some automotive seat fit parameters based on a representative Nigerian anthropometric data, to ensure an optimum fit between the vehicle seats and the occupants, as well as providing adequate accommodation. Anthropometric data of 863 Nigerians captured with special emphasis on the dimensions that are applicable in automotive seat design. A comparison made between the data obtained and that of five other countries. The proposed dimensions includes: seat cushion width (475mm); seat cushion length (394mm); seat height (340mm); seat lateral location (583mm); seat back height (480mm); seat back width (427mm); armrest height (246mm); headrest height (703mm); armrest surface length (345mm); backrest width (thoracic level) (524mm); seat adjustment (186mm); backrest width (lumbar level) (475mm) and distance between armrests (475mm). A comparison made between the proposed dimensions and those recommended by four other scholars for other populations. Finally, an ergonomic automotive seat suitable for the Nigerian population was designed using AutoCAD 2016 software based on the proposed established dimensions
Ergonomics ; Anthropometry ; Automotive Seat ; Design

Anthropometric study is one of the oldest branches of study in ergonomics where it serves a purpose in study of proportion and size for human body. One of the common methods used in anthropometric measurement is traditional measurement or direct measurement. However, Malaysia is still left behind other countries in development of national anthropometric database. Researchers in Malaysia are still relying on the traditional anthropometric (TA) measurement. There are several important factors that contribute to problems in TA such as accuracy, time, posture, identification of landmarks, instrument positions and orientations, and pressure exerted due to measuring equipment. In view of the fact that the difficulties of obtaining human anthropometry, it becomes necessary to propose a method which has less contact executed to respondent. This study aims to propose a new anthropometric measurement method using motion capture camera (MCC) method, later to develop the database for youth male population. A pilot test was done in order to confirm the measuring procedure as well as the flow of the study. Next, the Minitab statistical software used to check the validity and reliability of data using the tests of a) Accuracy-Pearson/Spearman Correlation b) BiasPaired T-Test c) Test-Retest Reliability-Pearson/Spearman Correlation d) Precision-Mean Absolute Difference and Relative Error Measurement. Results showed that the validity and reliability of this motion camera has successfully obtained and the anthropometric data for youth male respondents has successfully constructed. These findings can be used and expended to the national anthropometric database to be utilised in ergonomics design.
traditional anthropometry ; non-contact anthropometry measurements ; validity and reliability ; ergonomics design

OBJECTIVEIn this study, we aimed at exploring the association between work-related musculoskeletal disorders (WMSDs) and work organization based on a case-control study.

METHODSA total of 1938 workers who claimed to suffer from WMSDs were selected from Beijing, Henan, Hubei, and the Guangdong province. The control group consisted of 2009 workers employed in similar industries without severe disease or musculoskeletal discomforts. We used a modified version of the questionnaire developed by the NMQ and the DMQ to investigate individual and work-related factors.

RESULTSA total of 13 variables (P<0.1) were selected by the chi-square test and finally, 7 variables entered into the equation, with 6 variables reaching statistical significance (P<0.05). The odds ratios (OR) of 'work changing with season' and 'sufficient rest time' did not reach 1 (0.749 and 0.441, respectively). In addition, 'sufficient rest time' seemed to be the stronger protective factor according to its higher standardized coefficient. And 'repetitive work every minute', 'constantly repetitive work' (every day), 'shortage of site personnel', and 'often switching shifts with others' seemed to be the risk factors.

CONCLUSIONWork organization may have comprehensive effects on the occurrence of WMSDs. This pattern of associations suggests that further investigation into the mechanism of how work organization affects the prevalence of WMSDs is required.

Adult ; Case-Control Studies ; Chi-Square Distribution ; China ; epidemiology ; Cross-Sectional Studies ; Cumulative Trauma Disorders ; epidemiology ; etiology ; Demography ; Ergonomics ; standards ; Female ; Humans ; Logistic Models ; Male ; Musculoskeletal Diseases ; epidemiology ; etiology ; Occupational Diseases ; epidemiology ; etiology ; Personnel Staffing and Scheduling ; organization & administration ; Prevalence ; Risk Factors ; Seasons ; Surveys and Questionnaires ; Work Schedule Tolerance ; physiology ; Workplace ; organization & administration ; Young Adult

10 male subjects participated in the environmental simulation study to evaluate the operation ergonomics at high-temperature in the cockpit. Grip strength, perception, dexterity, reaction and intelligence were measured respectively during the tests at 40 degrees C and 45 degrees C, simulating the high-temperatures in a simulation cockpit chamber. Then the data obtained were compared to the combined index of heat stress (CIHS). The average values of each item of the subjects' performance at the two different temperatures are compared. The results indicated that CIHS exceeded the heat stress safety line after 45 min at 40 degrees C, grip strength decreased by 12%, and perception increased by 2.89 times. In contrast, at 45 degrees C, CIHS exceeded the safety line after 20 min, grip strength decreased by 3.2%, and perception increased by 4.36 times. However, Finger dexterity was less affected. Reaction ability was first accelerated, and then slowed down. The error rate in the intelligence test increased to a greater extent. At the high temperatures, the minimum perception was the most affected, followed by grip strength, reaction and finger dexterity were less affected, while the intelligence did not decline, but rise.
Adult ; Aerospace Medicine ; Aircraft ; Computer Simulation ; Ergonomics ; Heat Stress Disorders ; physiopathology ; Hot Temperature ; adverse effects ; Humans ; Male ; Young Adult