Effect of break-time on the upper extremity musculoskeletal disorder development and task performance of computer users

Work Related Occupational Musculoskeletal Disorder (WRMSD) developed due to excessive, repetitive and forceful motions of certain parts of the body. Musculoskeletal Disorder (MSD) problems begins initially with a minor discomfort and if no action was taken to overcome this problem it can develop to major injuries and deformation. According to a report from NIOSH Malaysia, there has been an increase in the occurrence of MSDs, especially in work that require continuous computer usage. Office workers who use computer intensively for instance more than 3 hours continuously without sufficient rest break tends to develop MSD problems. Previous studies shown than rest break can allow workers to relax muscles and reduces the possibility of developing physical and mental discomfort. However studies on an effective break time that can improve performance and reduce muscle work load on the upper extremity muscles among office workers in Malaysia are still lacking. A preliminary study was conducted to determine relationship between break time and other risk factors to the development of MSD. The effect of work rest schedule on the muscular load levels, performance and discomfort rate on the upper extremity muscles among computer users was studied. Hundred twenty questionnaires survey which was designed based on the Nordic Questionnaire and Body Discomfort Chart (BDC) were distributed to office workers in a company. The questionnaires were analyzed to determine various risk factors such as individual, physical and job characteristics that contribute to the development of MSD. Bivariate analysis using SPSS software showed that age have a significant positive correlation with discomfort that was 0.308 at (p=0.01); frequency of work rest showed higher negative correlation whilst working hour showed positive correlation to the presence of MSD discomfort. These findings suggests that more work rest with less persistent working hour can reduce the development of MSD problems. The effect of break time on performance was conducted using three different work rest schedules. Three thirty minutes of typing tasks was given to 15 respondents where one with no break, second with 1 min break and third with 30 seconds’ break. The muscle load, performance and discomfort level were measured. The result showed that 30 seconds microbreak at every 10 minutes interval reduces muscle load where EMG recorded lowest mean average- EMG (AEMG) which was 0.0350 ± 0.012 (mV) for flexor carpi ulnaris and radialis muscles and typing performance improved by 13.5% compared to 1 minute break and 20.14% compared to schedule with no breaks. At the end of the experiment, 71% of respondents recorded minimal discomfort for 30 seconds micro-break. As a conclusion 30 seconds micro-break is effective for office workers to practice during their continuous typing activity as it can reduce muscle load and improve their performance by reducing muscle discomfort on the upper extremity muscle. The limitation of this study was that computer users from different working background was not covered. In future work, the scope of study can be focused on the people who spend greater amount of time in computer gaming.

Preview Text FK 2018 53 IR.pdf Download (1MB) | Preview

Actions (login required)

View Item