Physical and psychological job demands and fatigue experience among offshore workers.

Offshore operations are generally challenging and hazardous, and the workers are exposed to conditions that may lead to fatigue. A cross-sectional study evaluated physical and psychological job demands and their associations with fatigue among offshore workers. The offshore workers (n = 251) completed a questionnaire including demographic/job details, Multidimensional Fatigue Inventory (MFI‒20), and Job Content Questionnaire (JCQ). Data were analysed using linear regression modelling. Results indicated that the physical (particularly performing repetitive motions and applying pressure with hands and wrists) and psychological (e.g., intense task concentration and fast working) job demands were relatively high. The total mean (SD) fatigue score (MFI‒20) was 56.3 (13.9). Individual factors (Body Mass Index ‒ BMI), physical job demands (awkward working postures, frequent moving/lifting heavy objects and doing lots of physical efforts) and psychological job demands (task interruptions by other people and doing an excessive amount of work) were the main variables associated with different dimensions of fatigue in the multivariate models. While physical fatigue was only associated with the physical job demands, both physical and psychological job demands were significantly associated with mental fatigue in the multivariate context. The findings have possible implications for job design and implementation of intervention programmes to promote health and performance of the employees.

Investigation of the multi-component ergonomics intervention effects on improving musculoskeletal outcomes and speech communication: A case study in open-plan offices.

BACKGROUND: Office workers are at high risk of developing musculoskeletal symptoms (MSS) due to improper workstations. Open-plan bank office employees must communicate with bank clerks properly and perform financial activity precisely, but noise is a factor that disrupts their communication. Therefore, MSS and annoying noise are two of the main problems in open-plan offices. OBJECTIVE: This study evaluated the effects of a multi-component intervention involving individual (employee ergonomics training) and physical (improvements in workstation design and work environment) ergonomic factors on musculoskeletal outcomes and speech communication in open-plan environments. METHODS: A preliminary survey was carried out to investigate the overall ergonomics problems, the tasks and time analysis, workstations setup, the prevalence of MSS (Nordic Musculoskeletal Questionnaire), physical discomfort (Visual Analogue Scale [VAS]), and posture (assessed by Rapid Upper Limb Assessment [RULA] method), environmental status (measurement of noise), and speech intelligibility (assessed by Speech Interference Level [SIL] method based on ISO 9921). The multi-component interventions were performed afterward based on the data collected. A baseline assessment and a 9-month follow-up assessment were conducted. RESULTS: The results showed a significant decrease in the prevalence of musculoskeletal complaints (shoulders, elbows, and low back), physical discomfort, and awkward working postures after the intervention. A considerable improvement was also found in speech intelligibility post-intervention. The post-intervention questionnaire survey also indicated that employees generally favored the redesigned workstations. CONCLUSION: The results support the effectiveness of implementing multi-component interventions in open-plan bank offices to improve musculoskeletal complaints and speech communication.

Psychometric properties of the Iranian version of the wheelchair seating discomfort assessment tool (WcS-DAT) - section II: a revised two-dimensional structure of comfort and discomfort to improve inclusive design practice.

PURPOSE: The objectives of the study were to: 1) validate the Wheelchair Seating Discomfort Assessment Tool (WcS-DAT - section II) in Iran, and 2) to determine whether or not the items on the scale address just one dimension (e.g., discomfort). METHODS: A descriptive-methodological study was performed among 109 (76 males and 33 females) full-time wheelchair users, aged 12-70 years in Tabriz, Iran. To develop the revised Iranian version of the WcS-DAT - section II, a standard "forward-backward" method was in the first step. Then, the content validity and construct validity of the tool was assessed based on feedback from an expert panel and factor analyses (exploratory and confirmatory), respectively. Sensitivity (using ceiling/floor effect), internal consistency (using Cronbach's α), and test-retest reliability (using Intraclass Correlation Coefficient - ICC) were also evaluated. RESULTS: Results established content validity, sensitivity, internal consistency (values of Cornbrash's α: 0.79-0.82), and test-retest reliability (values of ICC: 0.79-0.93) of the Iranian WcS-DAT - section II. Factor analyses revealed a two-factor structure (comfort and discomfort), for the scale, and thus confirmed its construct validity. CONCLUSIONS: The findings suggest that the Iranian version of WcS-DAT- section II is a reliable and valid tool for the evaluation of wheelchair seating comfort and discomfort in the Iranian population. The revised two-factor model of comfort/discomfort has potential implications for inclusive design research and practice.

The revised Iranian version of the Wheelchair Seating Discomfort Assessment Tool (WcS-DAT) is a valid tool to assess individual and wheelchair fit in the context of daily activities performed.A two-factor model of the instrument measuring wheelchair seating comfort and discomfort provides a more detailed understanding of the two constructs (e.g., comfort and discomfort), which is especially important in ergonomic evaluations and interventions.Additional attention to the specific needs of wheelchair using populations has a potential to improve the universal design of future products.

T-shaped handle set-up: effects of handle diameter, between-handle distance, workpiece orientation, working height, and exertion direction on two-handed torque strength, usability, comfort, and discomfort.

The use of both hands is often required for force/torque exertions, particularly when using hand tools. This study investigated the effects of handle diameter (3-5 cm), between-handle distance (0.5-1.5 shoulder span (SS), workpiece orientation (horizontal/frontal), working height (shoulder/elbow/knuckle), and exertion direction (clockwise/counter-clockwise) on maximum two-handed torque strength, usability and comfort/discomfort while using T-shaped handles. Participants (n = 20) performed 36 experimental conditions. The handle diameter had no significant main effect on torque strength. The 3 cm diameter handle was associated with better usability and comfort compared to other options. Higher torque values were recorded with between-handle distance of 1.0 and 1.5 SS, in frontal plane, in shoulder and knuckle heights, and in counter-clockwise direction. The between-handle distance of 1.0 SS had better comfort and higher usability than other conditions. Interactions between the between-handle distance and working height, between-handle distance and workpiece orientation, and workpiece orientation and working height were also significant.Practitioner summary: Effects of handle diameter, between-handle distance, workpiece orientation, working height, and exertion direction on torque exertions, and subjective measures when using T-shaped handles were evaluated. Higher levels of strength were measured with between-handle distance of 1.0-1.5 shoulder span, and in frontal plane, in shoulder/knuckle heights, and in counter-clockwise direction.

Effects of tool grip span, workpiece orientation, moving direction, and working height on two-handed torque strength and subjective measures.

BACKGROUND: Using both hands is regularly needed for force/torque exertions in many activities, especially when using hand tools. OBJECTIVE: To investigate the effects of tool grip span, workpiece orientation, moving direction, and working height on two-handed wrist U/R deviation torque strength, usability, comfort, and discomfort while using locking pliers. METHODS: Participants (n = 22) took part in an experimental study which evaluated the effects of tool grip span (4.5-6.5 cm), workpiece orientation (transverse/sagittal), moving direction (clockwise (CW)/counterclockwise (CCW)), and working height (shoulder/elbow/knuckle) on two-handed wrist U/R deviation torque, (dis)comfort, and usability while using locking pliers. RESULTS: The results showed no significant effect of tool grip span on wrist U/R deviation torque strength, but the locking pliers with 4.5 cm handle grip span led to more comfort and better usability. The two-handed wrist U/R deviation torque strengths were significantly higher in sagittal plane than in transverse plane, and in CW direction than in CCW direction. The highest values of two-handed wrist U/R deviation torque strength in sagittal and transverse planes were exerted in knuckle and elbow heights, respectively. CONCLUSION: The findings can be used to develop guidelines and recommendations with regard to daily and occupational activities which require the use of both hands for force exertion with manual hand tools.

Cognitive and balance performance of older adult women during COVID-19 pandemic quarantine: an ex post facto study.

Introduction: Isolation and self-quarantine can expose individuals, particularly older people, to cognitive and physical decline. Due to a reduction in their musculoskeletal and neural flexibility, older adults are more likely to be affected by quarantine limitations. This study aimed to investigate the effect of self-quarantine on cognitive and balance performance of older women during the COVID-19 outbreak. Material and methods: In a convenience sampling method, a total of 75 older adult women were recruited in this ex post facto study. The mini-mental state exam, single leg stance test, and timed up and go test were used to assess cognitive functions, static, and dynamic balance, respectively. Fall risk was measured by the Johns Hopkins assessment tool. Evaluations were performed before and after 7 months of quarantine due to the COVID-19 outbreak (November 2019 - June 2020), in which volunteers were at the lowest level of physical and social interaction. Results: No significant difference was observed in the mean static balance performance of the older adult women between the baseline and quarantine phases [p = 0.095, t (df) = -1.69]. The dynamic balance performance [p < 0.001, t (df) = 5.6] and cognitive status (p < 0.001, t = -7.4) decreased and the fall rate increased [p < 0.001, t (df) = 7.35] after 7 months of quarantine. Conclusions: It seems that self-quarantine can cause a decline in cognitive functions and dynamic balance performance of older women. It implies that the decrease in social interactions and physical activities caused by the limitations of self-quarantine put individuals at greater risk of cognitive impairment and increase their falling rate by impairing dynamic balance.

The effect of transcranial photobiomodulation on cognitive function and attentional performance of older women with mild cognitive impairment: a randomized controlled trial.

Introduction: Mild cognitive impairment (MCI) is a progressive age-related condition caused by physiological and structural changes in the brain, such as neurodegeneration and hypometabolism. Transcranial photobiomodulation (tPBM) is a neuromodulation technique that improves brain metabolism and oxygenation by irradiating red to near-infrared light on a specific area of the head. This study aimed to investigate the effect of multi-session tPBM on the cognitive capacities and attentional function of older women with MCI. Material and methods: In this randomized controlled trial, 42 older women with MCI were randomly assigned to 2 equal groups: real and sham. The mini-mental state examination (MMSE) and the attentional Go/No-Go task were used to examine the patients. On the right frontal-pole of the cortex, 5 sessions of 850 nm tPBM were given. Re-examinations were conducted on the participants. For the Go/No-Go task, the reaction time to the target (RTT), the percentage of correct trials (PCT), and the efficiency score (ES) were measured. Results: The findings revealed a significant interaction between group × time for MMSE (F (1, 40) = 20, p < 0.001, h2 = 0.33), and the post-hoc paired-samples t-tests revealed a substantial rise in the mean MMSE in the real group (t = 15.9; p = 0.001; d = 9.3). Additionally, for ES (F (1, 40) = 19, p < 0.001, h2 = 0.32), RTT (F (1, 40) = 17, p < 0.001, h2 = 0.38), and PCT (F (1, 40) = 13, p < 0.001, h2 = 0.31), a significant group × time interaction was discovered, and post-hoc paired-samples t-tests revealed a significant improvement in attention performance of the real group for increases in the mean of ES (F (1,40) = 20, p < 0.001, h2 = 0.33), (t = 5.3, p < 0.001, d = 0.034), decreases in the mean of RTT (t = 4.8; p = 0.001; d = -37.4), and increases in the mean of PCT (t = 2.67; p = 0.015; d = 6.3). Conclusions: According to the findings of this study, tPBM had a positive effect on older people's attention and cognitive abilities.

Work-related stress, self-efficacy and mental health of hospital nurses.

BACKGROUND: The limited research has focused on the relationship between work-related stress and self-efficacy in relation to mental health problems in nurses. OBJECTIVE: This multi-hospital cross-sectional survey investigated the relationships between work-related stress, self-efficacy and mental health status of hospital nurses in Tabriz, Iran. METHODS: Four hundred hospital nurses completed a questionnaire including demographic and job details, Health & Safety Executive (HSE) Management Standards Revised Indicator Tool (MS-RIT), General Self-Efficacy (GSE-10) scale, and General Health Questionnaire (GHQ-28). A three-step hierarchical logistic regression modelling was used. RESULTS: Work-related stress, self-efficacy and mental health problems were significantly related to each other. The results of the regression modelling revealed that working overtime and number of patients cared for were significant positive predictors, while job tenure as well as control and relationships dimensions of work stress were significant negative predictors of mental health problems, with the final model explaining 21% of the variance in the outcome measure. Addition of self-efficacy at step 3 did not result in a significant change in the variance from previous steps. CONCLUSIONS: The results provide further support for stress prevention strategies focused at the job (e.g., better organisation of work demands) and organisational (e.g., improving employee participation and involvement in work) levels.

Cognitive performance and electroencephalographic variations in air traffic controllers under various mental workload and time of day.

The aim of this study was to investigate the effects of mental workload (MWL) and time of day on cognitive performance and electroencephalographic (EEG) parameters of air traffic controllers. EEG signals recorded while 20 professional air traffic controllers performed cognitive tasks [A-X Continuous Performance Test (AX-CPT) and 3-back working memory task] after they were exposed to two levels of task difficulty (high and low MWL) in the morning and afternoon. Significant decreases in cognitive performance were found when the levels of task difficulty increased in both tasks. The results confirmed the sensitivity of the theta and beta activities to levels of task difficulty in the 3-back task, while they were not affected in the AX-CPT. Theta and beta activities were influenced by time of day in the AX-CPT. The findings provide guidance for application of changes in EEG parameters when MWL level is manipulated during the day that could be implemented in future for the development of real-time monitoring systems to improve aviation safety.

The Relationship between Cognitive Status and Retained Activity Participation among Community-Dwelling Older Adults.

Identifying retained activity participation to old age can improve age-related changes in balance and cognition function. Subjects ≥ 60 years were enrolled in this study. Balance and Cognitive function include working memory, executive function, and sustained and divided attention was evaluated with "Fullerton advanced balance", "n-back", "Wisconsin card sort", "sustain and divided attention test", respectively. In addition, retained activity participation was measured using the Activity Card Sort questionnaire. The univariate and multivariate regression analyses of different domains of retained activity participation were used as independent variables, including instrumental activity, low-effort leisure, high-effort leisure, and social activity on balance and specific domains of cognition. Seventy-seven subjects (65.3 ± 4.4 years, 61% female) were included. About 47% of older adults had a college education, 32.3% had a diploma, and 20.7% had elementary−middle education. These results show that retained instrumental activity had a relationship with working memory (ß = 0.079, p < 0.05). In addition, we found that retained high-effort leisure activity can increase balance, divided attention, and executive function score (ß = 0.1, ß = 0.05, ß = 0.02, p < 0.05). Moreover, there was a positive relationship between retained low-effort activity and sustained attention (ß = 0.08, p < 0.05). In addition, the coefficient of determination (R2) for balance, working memory, executive function, sustained, and divided attention were 0.45, 0.25, 0.13, 0.11 and 0.18, respectively. The study suggests that retained activity participation types may have various effects on balance and some selective cognitive components in older people.

Do older workers suffer more workplace injuries? A systematic review.

Aging populations are a dramatically increased worldwide trend, both in developed and developing countries. This study examines the prevalence of fatal and non-fatal work-related injuries between young (<45 years old) and older (≥45 years old) workers. A systematic literature review aimed at examining studies comparing safety outcomes, namely fatal and non-fatal injuries, between older and younger workers. Results show that 50% of the reviewed papers suggest that fatal injuries are suffered mainly by older workers, while the remaining 50% show no differences between older and younger workers. Regarding non-fatal injuries, 49% of the reviewed papers found no relationship between workers' age; 31% found increased age as a protective factor against non-fatal injuries; and 19% showed that older workers had a higher risk of non-fatal injuries than younger ones. This review suggests that older workers experience higher rates of fatal injuries, and younger workers experience higher rates of non-fatal injuries.

Investigation of hand muscle fatigue and its influential factors in manual tasks.

Muscle fatigue (MF) can lead to musculoskeletal disorders (MSDs) in the long term; however, it can be managed if the causes are well known. This study aimed to examine the grip force (GF) and grip fatigue (GFa) of employees with light, moderate and heavy manual tasks using a dynamometer and find their possible relationship with other factors. The nature of heavy manual tasks led to more experience of GFa and GF of the right hand. Moreover, the equal need for both hands in occupations with light and moderate manual tasks is the reason for more GFa in the left hand. In this primary study, the height, weight and age of subjects and their exposure to vibration had a decisive effect on GF. In order to determine the accurate effects of the aforementioned risk factors on MF, it is recommended for future studies to be performed on larger populations.

Effects of handle characteristics of manual hand tools on maximal torque exertions: a literature review.

The present study was conducted to review the literature on the effects of handle characteristics of manual hand tools including handle diameter, shape and material on forearm supination/pronation, wrist flexion/extension and wrist ulnar/radial deviation torque strengths to assist ergonomists and designers in developing guidelines to improve workstations and hand tool designs. Twenty-seven papers meeting the inclusion criteria were reviewed. The study provides different points that can be applied to improve the design of hand tools with an emphasis on handle diameter, shape and material, and highlights various methodological issues including interactions among variables affecting maximum torque strength, posture, torque exertion using one or two hands, torque exertions in multiple anatomical axes, using gloves, upper extremity anthropometry and test protocols, which should be considered in future research.

Does self-efficacy mediate the relationship between occupational stress and mental health problems? A study among nursing professionals.

Background: While it is acknowledged that self-efficacy plays a significant role in understanding consequences of occupational stress, no research has given much attention to the mediating effect of self-efficacy in the association between occupational stress and mental health (MH)problems. The aims of this study were to examine: (1) the associations between occupational stress, MH problems, and self-efficacy among nursing professionals, and (2) mediating effect of self-efficacy in the association between occupational stress and MH problems. Methods: A multi-hospital cross-sectional survey was adopted in eight hospitals in Tabriz, Iran. 389 nursing staff were recruited through a two-stage sampling procedure. Study variables included occupational stress (Health & Safety Executive [HSE] Management Standards RevisedIndicator Tool [MS-RIT]), mental health (General Health Questionnaire [GHQ-28]), and self efficacy (General Self-Efficacy [GSE-10]). Generalized structural equation modelling (GSEM)was applied. Results: Occupational stress (mean±SD=109.2±13.4), poor MH (41.9%), and low selfefficacy (mean±SD=17.7±4.9) were fairly common among the participants. The results showed significant direct effect of occupational stress on MH problems (ß=- 0.38, P<0.001). Indirect effect of occupational stress on MH problems through self-efficacy was not significant. Conclusion: The findings highlight the role of other mechanisms or factors than self-efficacy in the association between occupational stress and MH problems that should be established in future work.

Identification of factors related to behaviors associated with musculoskeletal pain among elementary students.

BACKGROUND: Musculoskeletal pains are among evident health problems in children and adolescents. Backpack carrying behaviors and the sitting postures are among behavioral factors associated with musculoskeletal pain in schoolchildren. Therefore, this study aims to identify the factors related to these important musculoskeletal behaviors, using Health Promotion Models. METHODS: In this cross-sectional study, a questionnaire was created based on PRECEDE Model and Health Belief Model and was administered to 673 Iranian students, whom were selected randomly from elementary schools of Hamadan, Iran, in 2018. RESULTS: The findings of the study revealed that proper sitting postures and backpack carrying were 42 and 33%, respectively. The findings also showed that predisposing factors including perceived susceptibility (p < 0.05, ß = 0.219), perceived severity (p < 0.05, ß = 0.166), perceived barriers (p < 0.05, ß = - 0.191), perceived self-efficacy (p < 0.05, ß = 0.188) and also enabling factors (p < 0.05, ß = 0.329) were significantly related to sitting behaviors. Moreover, backpack carrying behaviors had significant relationships with predisposing factors of perceived susceptibility (p < 0.05, ß = 0.198), perceived barriers (p < 0.05, ß = - 0.258), perceived self-efficacy (p < 0.05, ß = 0.185) and reinforcing factors (p < 0.05, ß = 0.208). CONCLUSIONS: It seems necessary for future preventive programs to take factors of musculoskeletal pains among children and adolescents into account.

Mismatch between jar opening demands and wrist torque strength of consumers in Iran.

This study evaluated the potential mismatch between vacuum-sealed jar opening demands and wrist torque strength of 758 (384 males and 374 females) participants aged 5-74 years in Iran. Wrist ulnar/radial (U/R) torque strength of participants and required torque for opening the existing jars (with 2 different sizes - 65 mm and 85 mm diameter lids) were measured using a digital angle torque adaptor and then compared together to identify any potential mismatch between them. The mismatch percentages were defined as the number of participants whose maximal wrist U/R torque strength were lower than the minimum required torque strength for opening the vacuum-sealed jars. Minimum required torque strength for opening the existing 65 mm and 85 mm vacuum-sealed jars were 4.1 Nm and 6.6 Nm, respectively (range = 4.1 Nm to 10.2 Nm). A considerable mismatch (range = 25%-100%) was found between the required torque strength for opening the existing jars and the wrist U/R torque strength of the study population, particularly for females and those aged 5-9 years. A torque limit of 1.8 Nm was proposed for opening jars for the entire population.

Perception of just culture and its association with work-related psychosocial factors in an Iranian industrial setting: Implications for prevention of errors.

BACKGROUND: A just culture is one in which the reporting of errors and near misses is supported without fear of retribution. The relationship of just culture and psychosocial factors at work has not been explored sufficiently in the literature. OBJECTIVE: To investigate the perception of just culture and its association with socio-demographic and work-related psychosocial factors among 302 employees in an industrial setting in Iran. METHODS: Just culture was assessed using the Just Culture Assessment Tool, and the Copenhagen Psychosocial Questionnaire was used for evaluation of psychosocial work factors (including influence at work, meaning of work, commitment to the workplace, predictability, rewards, quality of leadership, social support from supervisors, trust, and justice and respect). Data were analysed using t test, analysis of variance (ANOVA), and general linear regression analysis. RESULTS: The results indicated that the employees had a fairly positive view on their organisation's just culture, though there were some areas such as trust and balance that needed further attention. The psychosocial issues (particularly commitment to the workplace, meaning of work, social support from supervisors, and rewards) were not adequate from the employees' perspective. Predictability, rewards, and quality of leadership, were the significant psychosocial predictors of just culture in a multivariate regression model. CONCLUSIONS: The findings highlight the areas that need to be considered to improve the experience of organisational just culture, which is important from the point of view of prevention of safety errors and incidents.

Electromyographic evaluation of different handle shapes of masons' trowels.

The effects of five different handle shapes of masons' trowels on muscle activity of the arm and forearm muscles (through electromyographic measurements of the biceps brachii [BB], flexor digitorum superficialis [FDS], pronator teres [PT] and extensor carpi ulnaris [ECU]) were evaluated in a simulated masonry task. The results showed a significant effect of handle shape on the muscle activity of the BB, PT and ECU. The muscle activity of the extensor (ECU) and flexor (FDS) were generally larger than those of the supinator (BB) and pronator (PT). Some improvements were found in terms of muscular exertions with prototype designs C, D and E, which had either handles with variable diameter (designs C and E) or a slightly bent handle (design D). These findings have practical implications for the design of single-handle hand tools but may need further validation for specific contexts of use.

Effects of Cognitive and Physical Loads on Dynamic and Static Balance Performance of Healthy Older Adults Under Single-, Dual-, and Multi-task Conditions.

OBJECTIVE: The aim of this study is to examine the effects of cognitive and physical loads on dynamic and static balance performance of healthy older adults under single-, dual-, and multi-task conditions. BACKGROUND: Previous studies on postural control in older adults have generally used dual-task methodology, whereas less attention has been paid to multi-task performance, despite its importance in many daily and occupational activities. METHOD: The effects of single versus combined (dual-task and multi-task) cognitive (to speak out the name of the weekdays in a reverse order) and physical (with three levels including handling weights of 1, 2, and 3 kg in each hand) loads on dynamic and static balance performance of 42 older adults (21 males and 21 females) aged ≥60 years were examined. Dynamic and static balance measures were evaluated using the Timed Up and Go (TUG) and stabilometer (sway index) tests, respectively. RESULTS: The TUG speed of female participants was generally slower than that of male participants. Age had no effect on balance performance measures. Under dual-task conditions, cognitive load decreased the dynamic balance performance, while the physical task levels had no effect. The dual-task conditions had no impact on the static balance performance. The effects of cognitive and physical loads on dynamic balance performance varied under dual- and multi-task conditions. CONCLUSION: The findings highlight differences between dual- and multi-task protocols and add to the understanding of balance performance in older adults under cognitive and physical loads. APPLICATION: The present study highlights differences between dual- and multi-task methodologies that need to be considered in future studies of balance and control in older adults.