Thai Journal of Ergonomics

Ergonomic risk assessment and musculoskeletal disorder in the parcel sorting process

Thanwa Bamrungsin — 2025-06-29

This research is a survey study aimed at examining the prevalence of musculoskeletal disorders and assessing ergonomic risks among a group of 22 parcel delivery workers. The study uses the Standard Nordic Musculoskeletal Questionnaire to examine the prevalence of musculoskeletal disorders and the Rapid Entire Body Assessment (REBA) to assess ergonomic risks. The study found that all participants were male, with 63.00% aged between 36-45 years and an average work experience of seven years. Over the past 12 months, the top three body parts where participant experienced disorders were Lower back (86.00%), Shoulders/neck (77.00%), and Upper back (68.00%). Over the past seven days, the top three body parts where participants experienced disorders were Lower back (18.00%), Shoulders/neck (13.00%), and Upper back, legs/thighs, and feet/ankles (9.00% each). The REBA assessment results for the parcel sorting stage showed that for the left side risk assessment, the majority of participants (66.00%) had a risk score of ≥ 11, indicating a very high risk that requires immediate improvement. For the right-side risk assessment, the majority of participants (62.00%) had a risk score of 8-10, indicating a high risk that requires further analysis. For the parcel preparation stage, the majority of participants (58.00%) had a risk score of ≥ 11, indicating a very high risk that requires immediate improvement. The REBA assessment for the right side showed that the majority of participants (60.00%) had a risk score of ≥ 11, also indicating a very high risk that requires immediate improvement. The results of the ergonomic risk assessment using the REBA method for the parcel sorting stage and parcel preparation stage on vehicles indicated that the risk levels ranged from high to very high. This may be due to employees needing to bend down to read details on every package and lift packages from conveyor belts onto truck. This is attributed to improper working postures or unsuitable workstations. The study’s results can be used as a basis for improving workstations and implementing preventive measures or guidelines to improve work practices, reducing musculoskeletal disorders and ergonomic risks.

The effectiveness of handle insulated materials for reducing hand arm vibration among steel-plate polishing workers using air-angle grinders: A case study in an automotive part manufacturer, Chonburi province

Arunsiri Wongsawat — 2025-06-29

The use of metals is common in the automotive manufacturing industry as the main raw materials for various processes. These processes often involve the use of grinding and polishing machines, which can expose workers to vibrations that may have negative effects on their health. The main aim of this study is to investigate the levels of hand-arm vibrations experienced by workers using air-angle grinding machines to polish metal plates. The research seeks to develop a covering material for the handles, compare vibration measurements on the hand-arm before and after attachment of the covers, and assess the workers’ satisfaction levels post-attachment. To achieve these objectives, two different types of handle covers were designed and applied to the air-angle grinding machines used for polishing metal plates. Experiments were conducted with a sample group of 10 workers who met specific criteria. Vibration levels were measured before and after attaching the cover in the frequency range of 6.3-1250 Hz. along the X, Y, and Z axes. There search methodology involved the use of a questionnaire, Hand-arm meter, and the Wilcoxon Signed-Ranks test statistic to compare experimental results. The results showed a significant decrease in overall vibration acceleration after attaching both types of handle covers and grinding a 1 mm. thick steel plate for 2 minutes. The statistical significance level was P = 0.005. Before the experiment, the acceleration value was 4.97 m/s². After attaching material type 1, it decreased to 2.71 m/s², a reduction of 45.5%. Material type 2 resulted in a vibration level of 3.34 m/s², a reduction of 32.8%. Workers reported high satisfaction levels with material type 1, while material type 2 received a moderate rating. In the discussion, It was noted that although attaching the handle covers reduced vibration levels, they still exceed the standard threshold of 2.5 m/s² that necessitates action. It was suggested that different grip postures or handle thicknesses could potentially impact the level of hand-arm vibration exposure.

Ergonomics risk reducing for bamboo stick cutting process among the bamboo weaving workers: a case study of Nonsawang Community, Buntharik District, Ubon Ratchathani Province

Ratchanee Joomjee — 2025-06-29

This quasi-experimental research aimed to study ergonomic problems, ergonomic management, and the results of ergonomic management among the bamboo weaving workers in the Nonsawang community, Buntharik district, Ubon Ratchathani province. The sample size was 30 people. Data were collected by questionnaire and the Rapid Upper Limb Assessment (RULA) technique and analyzed using descriptive and inferential statistics (Wilcoxon Signed Ranks Test). The results revealed that most bamboo weaving workers had reported musculoskeletal disorders (MSDs) in the past 6 months, with the highest prevalence rates of symptoms being shoulder (100.00%), neck (96.07%), and lower back (93.30%). The risk assessment carried out by applying RULA showed a high level of risk for all the tasks. In this study, we are designing the bamboo stick-cutting station. After the design of the bamboo stick-cutting station, the effects on working time increased by 1.28 pieces per second, and the mean RULA score was reduced from 6.80 (very high risk; implement change now) to 4.80 (moderate risk; further investigation; change soon). This study showed the effect of a new stick-cutting station, which can reduce working time and ergonomic risk for workers.

Knowledge, attitude, and safety behaviors among Myanmar workers: A case study in a small construction company in Songkhla, Thailand

Saowanee Praphatsorn — 2025-06-29

This study aimed to achieve two main goals: (1) to assess the knowledge, attitudes, and safety behaviors of Myanmar workers in a small construction company in Songkhla Province; and (2) to explore the relationship between personal factors, knowledge, attitudes, and safety behaviors of these workers. The research focused on 30 foreign workers from a small construction company in Songkhla Province, representing the whole workforce. Data collection was conducted using a questionnaire, followed by statistical analysis, including frequency, percentage, mean, standard deviation, Fisher’s exact test, and Spearman's rank correlation analysis. The findings showed that foreign workers had a moderate level of safety knowledge, but their attitudes and behaviors towards safety were highly positive. However, no significant link was found between personal factors, knowledge, attitudes, and safety behaviors. This lack of significant correlation suggests that other factors, such as the quality of training or work environment, may play a more critical role in influencing safety behaviors. The results highlight the need for more tailored and context-specific safety interventions, which could be beneficial to organizations by improving safety outcomes and worker welfare.

Factors affecting the behavior of using herbal medicines to relieve muscle aches among people, Wat Bot District, Phitsanulok Province

Pemika Poonpin — 2025-06-29

This descriptive research aimed to study the factors affecting the behavior of people using herbal medicines to relieve muscle aches in Wat Bot District, Phitsanulok Province. The study sample consisted of 353 people. They were selected using a stratified random sampling technique. A questionnaire was used as the instrument for data collection. Descriptive statistics and stepwise multiple regression analysis were used for data analysis. The study results showed that knowledge and health literacy were at a high level, while attitudes, satisfaction, trustworthiness, marketing mixture, and behavior toward using herbal medicines to relieve muscle aches among people were at a moderate level. The factor with the highest predictive power on the behavior of using herbal medicines to relieve muscle aches among people was marketing mixture, followed by health literacy, knowledge, and attitudes, respectively. Four predictors could co-predict the behavior of using herbal medicines to relieve muscle aches among people at 16.4% with a statistical significance of 0.05. These research results indicate that related agencies should develop a marketing mixture, increase health literacy, educate, and adjust a positive attitude towards herbal medicines to relieve muscle aches continuously and consistently.

Relationship of working posture and musculoskeletal disorders among garment operators case study: Warin Market, Warinchamrap District, Ubonratchathani Province

Nipaporn Khamhlom — 2025-06-29

This Cross-sectional analytical study evaluated the working posture and the occurrence of self-reported musculoskeletal disorders among 30 garment operators in Warin market Warinchamrap district, Ubonratchathani province. A questionnaire and direct observations of working postures using the rapid upper limb assessment (RULA) method were used. Demographic characteristics were analyzed by descriptive and inferential statistics. The relationship between factors was analyzed using the univariate and multiple logistic regression. The results showed that all garment operators were female (66.70%) with the average age of 45.76 ± 8.83 years old. Most operators had a primary school education (66.70%). A high prevalence of musculoskeletal disorders, particularly in the upper back (66.70%), thigh (60.00%) and waist (55.30%) was found. The average RULA score of 5.7 indicates significant ergonomic issues with the sewing workstations. Most garment operators were found to be at high risk for musculoskeletal disorders, requiring immediate investigation and adjustments to their work practices. Individual factors and work-related factors associated with musculoskeletal disorders in the multiple logistic regression models. The findings add to the understanding of the working posture of those jobs involving sewing activities and emphasize the need for ergonomic interventions to reduce musculoskeletal symptoms in the future.

The improvement of workstation for reducing ergonomic risks in drug dispensing task among pharmacist at a hospital, Chonburi Province

Wisuthipong Sawetprasart — 2025-06-29

Pharmacists' medication dispensing work carries ergonomic risks due to working postures that may adversely affect the musculoskeletal system. This study aimed to improve the medication dispensing workstation in the outpatient pharmacy and compare the ergonomic risks before and after the improvement. A quasi-experimental research design was employed. The sample consisted of 10 voluntary participants selected through purposive sampling based on inclusion criteria. Data were collected using general information questionnaires, the Rapid Upper Limb Assessment (RULA) to evaluate upper body ergonomic risks, and electromyography devices. Data were analyzed using the Wilcoxon signed-rank test. The results revealed that after improving the workstation, the ergonomic risk—specifically the inappropriate working posture of the right upper body as assessed by RULA—significantly decreased from very high risk to moderate risk at the 0.05 significance level. However, the RULA assessment for the left side did not show a significant change (P < .08). The percentage of maximum muscle contraction significantly decreased for the right anterior deltoid (P < .05), left anterior deltoid (P < .05), right middle deltoid (P < .05), left middle deltoid (P < .05), right biceps brachii (P < .05), left biceps brachii (P < .05), right upper trapezius (P < .05), and left upper trapezius (P < .05). In conclusion, the study indicates that improving the workstation according to ergonomic principles can effectively reduce ergonomic risks for dispensing personnel. It is recommended that this approach be used as a guideline for designing other workstations in the future.

Factors associated with eye fatigue of workers in the electronics industry

Siripat Chuangkrud — 2025-06-29

This cross-sectional analytic study aimed to study risk factors correlated with eye fatigue of workers in the electronics manufacturing industry. There were 300 electronic workers included into the study. Data was collected by using the structured questionnaire and the measurements of visual acuity and the lighting intensity by the digital Lux meter. The eye fatigue examination was performed by using Critical Flicker Fusion (CFF) test and analyzed by comparing CFF value after 4 hours working to the CFF value before operation. The results showed that most workers were female (86.33%) with an average age of 25-35 years and working experience of less than 5 years. The prevalence of eye fatigue was 42.00%. The risk factors which significantly associated with eye fatigue were identified by multiple logistic regression analysis. Those standing posture workers had higher risk for eye fatigue than those of sitting work posture (ORadj=2.05, 95% CI=1.17-3.59), and workers with abnormal eye symptoms related to eye fatigue had higher risk than workers without abnormalities (ORadj=3.84, 95% CI=2.23-6.60). The spot measurement of lighting indicated that 7% of workstations did not meet the standard and most stations were at wire winding section. These findings of risk factors are useful for health monitoring and surveillance program of workers, particularly, who had visual abnormalities in action to prevent eye related diseases of electronic workers.