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BACKGROUND: Dairy industry workers face numerous ergonomic risk factors in their workplace, including improper posture, manual material handling, and musculoskeletal disorders (MSDs). Fewstudies have been conducted on the correlation of postural stress, MSDs, and chronic fatigue among workers in the dairy industry. OBJECTIVE: This study aimed to investigate the relationship between the level of postural stress, MSDs, and chronic fatigue in a dairy company. METHODS: In this cross-sectional study, 260 male workers were included in the research based on specific inclusion criteria. The Cornell Musculoskeletal Discomfort Questionnaire, Chalder Fatigue Scale, and a researcher-made demographic questionnaire were used to collect data. The posture of workers was evaluated using RULA and REBA software, and the evaluation of the manual lifting of loads was assessed using the WISHA lifting calculator. Finally, the collected data were entered into the SPSS software version 26.0 and analyzed. RESULTS: The findings revealed a significant statistical relationship between the level of postural stress and chronic fatigue and a significant positive correlation between MSDs and chronic fatigue. Furthermore, a statistically significant relationship was observed between MSDs, chronic fatigue, and ergonomics training experience. CONCLUSIONS: The results obtained in this study support the notion that high levels of postural stress and MSDs can produce an increase in chronic fatigue among workers, and lack of ergonomics training for workers can increase both MSDs and chronic fatigue. Therefore, it is necessary to carry out intervention measures in the field of ergonomics management in similar industries through the implementation of ergonomic intervention programs with a focus on proactive and preventive measures and the use of participatory ergonomic programs and educational demands assessment.

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OBJECTIVES: Despite a rise in automation, workers in the petroleum refining and petrochemical manufacturing industry are potentially exposed to various chemicals through inhalation while performing routine job duties. Many factors contribute to the degree of exposure experienced in this setting. The study objective was to characterize the impact of workplace conditions, anthropometric variability, and task orientation on exposure for a simulated routine operations task. METHODS: A chemical exposure laboratory simulation study was designed to evaluate the dependent variable of chemical exposure level in the breathing zone for methane and sulfur hexafluoride. The independent variables were (i) posture of the worker, (ii) worker anthropometry, (iii) process configuration, and (iv) gas density. RESULTS: Pipe height was a significant predictor of gas concentration measured in the breathing zone when located in a position that encouraged the gas to enter the breathing zone of the worker. Worker anthropometry had a major impact; tall worker's (male) chemical concentrations exceeded those of the short worker (female) for methane simulations but the opposite resulted for sulfur hexafluoride. Also, worker posture had a significant impact on gas exposure where nonneutral postures were found to have higher levels of chemical concentration. CONCLUSIONS: The study findings indicate that the breathing zone location is altered by posture and worker height, which changes the exposures relative to the emission source depending on the gas density of the chemicals that are present. As a result, qualitative risk assessment cannot be performed accurately without accounting for these factors. Practically, controls may need to account for worker size differences and posture adaptations.

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PURPOSE: Precision handicraft workers are often exposed to stressful postures and poor working conditions while performing different jobs, that are directly associated with the development of musculoskeletal disorders (MSDs). This cross-sectional study aimed at evaluating the prevalence of MSDs and contributing risk factors among male precision handicraft workers. METHODS: 334 handicraft workers involved in different precision activities: 125 gemstone cutters, 98 miniature painters, and 111 metal craft workers, were surveyed. Information about the prevalence of musculoskeletal symptoms and work-related factors was collected using the self-reported questionnaire and direct observation methods, viz. rapid upper limb assessment (RULA) and rapid entire body assessment (REBA). Chi-square test was performed to analyze the association of MSD symptoms between the handicraft occupations. Further, binary logistic regression was used to identify the potential risk factors for MSD symptoms among workers. RESULTS: In all occupational groups, most participants reported high prevalence of MSDs primarily in the neck (61.6%), lower back (74.8%), and knee (54.7%) regions. Results revealed that age, work experience, prolonged work hours, sustained awkward posture, continuous work without break, extensive work pressure, and poor job control increased the risk of MSD symptoms in different body regions, while with a higher level of education, MSDs in the neck and lower back regions reduced. CONCLUSION: The findings indicated incompatibility between precision handicraft workers and the occupational environment. Logistic regression models showed significant contribution of physical and psychosocial work-related factors in developing MSD symptoms. Ergonomic interventions are imperative to evade adverse consequences on the occupational health of precision craft workers.

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Background: A change in posture brings about a significant alteration in cardiovascular functions. The squat test has been used to study autonomic function in White Europeans but not Black Africans. The aim of this study is to determine the cardiovascular effects of postural stress in Black African non-diabetics and Type-2 diabetics. Method: Blood pressure (BP) and heart rate (HR) was measured in 40 non-diabetics and 40Type-2 diabetics in sitting, standing from sitting, squatting and standing from squatting positions Difference in BP and HR between consecutive positions was tested using 2- way mixed ANOVA. Proportions of those who showed orthostatic hypotension and hypertension were compared with Fishers exact test. Significance was set at p <0.05. mmHg Δ: BP and HR changes evoked by standing from sitting were not different, however squatting evoked greater increase in BP in diabetics(change (Δ) SBP: 5.85±9.95 vs 17.40±13.75mmHg: Δ DBP: 0.15 ± 6.89 vs 5.10 ± 7.59 mmHg:Δ MABP:2.02 ± 6.98 vs 8.63 ± 9.34 mmHg ,p <0.05) and standing from squatting evoked greater fall BP in diabetics (ΔSBP: -9.80±13.89 vs -24.35±16.03 mmHg; Δ MABP:-2.02±6.98 vs -8.63±9.34 mmHg: Δ PP: -2.28 ±15.35 vs -14.50 ±11.96 mmHg, p < 0.05) while Δ HR did not differ. A higher proportion of diabetics showed SBP and DBP orthostatic hypertension. Conclusion: Relative to the non-diabetics, diabetics showed greater BP but not HR responses to postural stress.

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AIMS: Haemodynamic assessment during stress testing is not commonly performed in patients with heart failure with reduced ejection fraction (HFrEF) because of its invasiveness, lower feasibility, and safety concerns. This study aimed to assess the haemodynamic characteristics of patients with HFrEF in response to non-invasive preload stress during dynamic postural alterations achieved by combining both semi-sitting position and passive leg-lifting and to evaluate whether combined postural stress could be used for risk stratification in these patients. METHODS AND RESULTS: For this study, 101 patients with HFrEF and 35 age-matched and sex-matched healthy controls were prospectively recruited. After all standard echocardiographic measurements were obtained in the left decubitus position, all subjects underwent postural stress testing, which consisted of changing from semi-sitting position to passive leg-lifting. During a median follow-up period of 12.2 months, 21 (21%) patients developed adverse cardiovascular events. In patients without adverse cardiovascular events, the stroke volume index (SVi) significantly changed from 28 ± 8 to 35 ± 10 mL/m2 (P < 0.001) during combined postural stress. By contrast, ΔSVi during combined dynamic postural stress was significantly smaller in patients with cardiovascular events than in those without events (ΔSVi 3.4 ± 4.0 vs. 6.4 ± 3.8 mL/m2 , P = 0.002), which indicated severely diseased heart operated on a relatively flat portion of the Frank-Starling curve. In a multivariate Cox proportional hazard analysis, ΔSVi (hazard ratio 0.81, P = 0.02) was an independent predictor of future adverse cardiovascular events. CONCLUSIONS: The combined assessment of dynamic postural stress is a non-invasive, simple, quick, and easy-to-use clinical tool for assessing preload reserve and risk stratification in HFrEF patients.

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In postural stress, an increased preload volume leads to higher stroke volume (SV) according to the Frank-Starling law of the heart. The present study aimed to evaluate the hemodynamic response to postural stress using non-invasive inert gas rebreathing (IGR) in patients with normal as well as impaired left ventricular function. Hemodynamic measurements were performed in 91 patients undergoing cardiac magnetic resonance imaging (CMR). Mean cardiac output and SV determined by IGR were 4.4±1.3 l/min and 60±19 ml in the upright position, which increased significantly to 5.0±1.2 l/min and 75±23 ml in the supine position (P<0.01). Left ventricular systolic function was normal [ejection fraction (EF) ≥55%] in 42 patients as determined by CMR. In 21 patients, EF was mildly abnormal (45-54%), in 16 patients moderately abnormal (30-44%) and in 12 patients severely abnormal (<30%). An overall trend for a lower percentage change in SV (%ΔSV) was indicated with increasing impairment of ejection fraction. In patients with abnormal EF in comparison to those with normal EF, the %ΔSV was significantly lower (13% vs. 22%; P=0.03). Non-invasive measurement of cardiac function using IGR during postural changes may be feasible and detected significant difference in %ΔSV in patients with normal and impaired EF according to the Frank-Starling law of the heart. Several clinical scenarios including cases of heart rhythm disturbances or pulmonary or congenital heart disease are worthy of further investigation.

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AIMS: A large number of workers including women are involved in the informal sector in India. A majority of them are engaged in agricultural sectors. The agricultural workers have to perform their jobs by putting manual labor and are exposed to different occupational stresses. The present study was aimed to evaluate postural stress and prevalence of musculoskeletal disorder (MSD) of women cultivators engaged in uprooting job of rice cultivation. SETTINGS AND DESIGN: This cross-sectional study was conducted on 166 women cultivators from different districts of West Bengal state, India. MATERIALS AND METHODS: Prevalence and intensity of MSDs of the cultivators were evaluated by Nordic questionnaire and 10-point body part discomfort scale. Work rest pattern and postural pattern were studied by direct observation method. Postural stress was assessed by OVAKO Working Postures Analysis System (OWAS), Rapid Entire Body Assessment (REBA), Rapid Upper Limb Assessment (RULA), and Quick Exposure Checklist (QEC) methods and as well as by measuring center of gravity. RESULTS AND CONCLUSIONS: MSD was highly prevalent among the study participants. Lower back, hip, wrist, shoulder, and knee were highly affected. Higher prevalence of MSDs among the cultivators may be because of prolonged working hours and awkward postures. The women cultivators had to start their day before dawn to finish off their household chores such as cooking, cleaning, washing clothes and dishes, etc., before they moved off to the fields, which altogether impose them under additional stress. It may be suggested that ergonomic interventions such as modifying work-rest schedules, improving work postures, and introducing new design hand tools should be considered for improving work condition of the women cultivators.

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The present study aimed to design a sitting stool for fish processing worker to reduce the postural stress during work. The study was conducted on 74 male and female fish processing workers selected randomly. The Musculoskeletal Disorder (MSD) of the subjects was assessed by the modified Nordic Questionnaire method. The body joint angles were measured by a digital goniometer. The results revealed that MSD was highly prevalent in lower back region in both male (78.57%) and female (93.47%) workers. The results of body joint angles suggested a high degree of forward bending during work. Efforts were made to design a sitting stool considering the human factors of the users to reduce the postural problems. The stool was designed by considering 5th and 95th percentile values of different anthropometric dimensions of the male and female workers. Paired comparison tests were employed to determine optimum dimensions of the stool for ensuring the compatibility of the physical characteristics of the stool with human body. From the results of paired comparison test and anthropometric characteristics of the users, physical dimensions of the sitting stool were settled for final designing. From the results, the height of the stool was determined separately for male and female workers. In the suggested design the height of the seat was 25cm for male and 20cm for female where the length and depth of the seat were 40cm and 32cm respectively for both sexes.A mechanical system was incorporated in the design so that the same stool could be used by the male and female workers. Subjective evaluation indicated that most of the subjects (>75%) rated the seat as good or very good. The joint angle study with suggested seat showed improved working posture.

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BACKGROUND: Realizing population-level discomfort evaluation and control of common static posture holding tasks requires an understanding of the inter-individual variation in discomfort perception. However, little research is available. OBJECTIVE: This study aimed to determine the types of mathematical probability distribution suitable for modeling population discomfort distributions of various static posture holding tasks and characterize how the magnitude of inter-individual variation in perceived discomfort varies across static posture holding tasks. SUBJECTS: Ten male and ten female subjects participated. METHODS: The participants conducted static posture holding for a set of 180 short-duration (20-second-long) static posture holding tasks and subjectively rated the overall perceived discomfort for each task using the Borg CR-10 discomfort scale. Statistical analyses were conducted according to the study objectives. RESULTS: The static posture holding tasks exhibited multifarious discomfort distribution patterns. Probability distribution identification analyses indicated that no single distribution type could represent population discomfort distributions universally across different static posture holding tasks. Sample standard deviation of discomfort ratings data quantifying the magnitude of inter-individual variation in discomfort perception varied considerably across static posture holding tasks. It seemed to have a positive relationship with sample mean within the range of the experimental conditions. CONCLUSIONS: Population-level evaluation of discomforts associated with static posture holding tasks must be based on careful examinations of empirical discomfort distributions.

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BACKGROUND: Few studies have investigated mathematical characteristics of the discomfort-time relationship during prolonged static posture holding (SPH) on an individual basis. Consequently, the discomfort-time relationship is not clearly understood at individual trial level. OBJECTIVE: The objective of this study was to examine discomfort-time sequence data obtained from a large number of maximum-duration SPH trials to understand the perceived discomfort-posture holding time relationship at the individual SPH trial level. METHOD: Thirty subjects (15 male, 15 female) participated in this study as paid volunteers. The subjects performed maximum-duration SPH trials employing 12 different wholebody static postures. The hand-held load for all the task trials was a ``generic'' box weighing 2 kg. Three mathematical functions, that is, linear, logarithmic and power functions were examined as possible mathematical models for representing individual discomfort-time profiles of SPH trials. RESULTS: Three different time increase patterns (negatively accelerated, linear and positively accelerated) were observed in the discomfort-time sequences data. The power function model with an additive constant term was found to adequately fit most (96.4%) of the observed discomfort-time sequences, and thus, was recommended as a general mathematical representation of the perceived discomfort-posture holding time relationship in SPH. CONCLUSION: The new knowledge on the nature of the discomfort-time relationship in SPH and the power function representation found in this study will facilitate analyzing discomfort-time data of SPH and developing future posture analysis tools for work-related discomfort control.

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