1.The Relation Of Risk Factors And Musculoskeletal Discomfort Among Manual Material Handling Workers In Malaysian Automotive Industries
Mirta Widia ; Siti Zawiah Md Dawal ; NukmanYusoff
Malaysian Journal of Public Health Medicine 2016;Special Volume(1):124-133
Most studies have examined the association of ergonomic risk factors and musculoskeletal discomfort in developed countries. Meanwhile the data are still lacking in developing countries such as Malaysia. The aim of this study was to determine the relation between risk factors and musculoskeletal discomfort among manual material handling workers in Malaysian automotive industries. A total of211 manual material handling workers from automotive industries completed a set of questionnaire on the individual, physical and environmental factors and the prevalence of musculoskeletal discomfort. The Chi-Square test and logistics regression analysis were used to determine the relationship of the risk factors and musculoskeletal. The findings highlighted that job tenure was significantly correlated with musculoskeletal discomfort among the workers (OR=2.33-5.56). The most significant physical risk factor that was associated with musculoskeletal discomfort was bending the trunk forward slightly, hands above knee level, which was significantly related to lower back discomfort (OR=5.13, 95%CI=1.56-16.8), thigh discomfort (OR=5.1, 95%CI=1.01-25.53) and wrist discomfort (OR=3.65, 95%CI=1.06-12.53). Twisting of the trunk (over 45o) and bending sideways were significantly associated to lower back discomfort (OR=4.04, 95%CI=1.44-14.44), and thigh discomfort (OR=4.3, 95%CI=1.29-8.50). The findings also highlighted that environmental factors was associated with musculoskeletal discomfort (p < 0.05. Musculoskeletal discomfort can be reduced by lowering work-related risk factors among automotive manual material handling workers, particularly by focusing on significant factors, including job tenure, bending or twisting postures and environmental factors.
2.Psychophysical and physiological study of asymmetric lifting and lowering task for Malaysian males
Mirta Widia, Siti Zawiah Md Dawal and NukmanYusoff
Malaysian Journal of Public Health Medicine 2016;16(Supplement 2):99-105
Extensive research has been carried out over the years to determine the maximum acceptable weight that a worker
is capable of lifting in a given situation among the Occidental populations in the Europe and US. At present, there is
a scarcity of studies in which lifting frequency is used as the measuring variable, especially in developing countries
such as Malaysia. Therefore, the objective of this study is to determine the effects of lifting loads on the maximum
acceptable frequency limit (MAFL), physiological response (muscle activity) and rating of perceived exertion (RPE)
for asymmetric lifting and lowering tasks of Malaysian males.Ten male subjects are recruited in this study and they
perform asymmetric lifting and lowering tasks repetitively for 30 minutes. Two lifting loads are considered (1) 1 kg
and (2) 5 kg. Each of the subjects adjusts his frequency of lifting using a psychophysical approach. The subjects are
instructed to perform the lifting and lowering task as fast as they could over duration of 30 minutes without
exhausting themselves or becoming overheated. Electromyography (EMG) signals are recorded from four muscles
(Right Erector Spinae (RES), Left Erector Spinae (LES), Right Trapezius p Descendenz (RTD) and Left Trapezius p
Descendenz (LTD) and analysed in terms of the normalized MVC during asymmetric lifting and lowering tasks. The
ratings of perceived exertion (RPE) for four body parts (arms, lower back, shoulders and entire body) are also
collected after the subjects have completed the lifting and lowering task. The mean frequency of the lifting and
lowering task obtained from the experiment is 13.41 and 9.66 times/minute for a lifting load of 1 and 5 kg,
respectively. The results of the independent sample t-test show that load has a statistically significant effect on the
maximum acceptable frequency limit (p < 0.05). However, it is found that even though there is an increase in muscle
activity and RPE with an increase in lifting load, there is no significant difference in the overall mean muscle activity
and RPE (p > 0.05). The percentage decrease in the maximum acceptable frequency for Malaysian males is higher
than the Occidental populations for both of the loads investigated in this study.
3.The Mental Workload And Alertness Levels Of Train Drivers Under Simulated Conditions Based On Electroencephalogram Signals
Nurul Izzah Abd Rahman ; Siti Zawiah Md Dawal
Malaysian Journal of Public Health Medicine 2016;Special Volume(1):115-123
It was suggested by most researchers that train drivers’ workload and alertness levels attribute to train accidents. The main objective of this study is to determine the significant patterns of mental workload and alertness levels of train drivers with respect to the conditions. The data are collected from simulation experiments on 15 professional train drivers. The simulation experiments are performed under three driving conditions (i.e. daytime, rainy daytime and rainy night) using a train driving simulator set. Electroencephalogram (EEG) signals are collected from six significant points on the body of the subjects. It is found that the mental workload of the train drivers tends to be high during rainy night driving condition and sleepiness occurs which is indicative of low vigilance. The beta amplitude increases under rainy night driving condition which may be attributed to viewing difficulties while driving in the dark. The results reveal that there is a significant different between each session (p = 0.042) especially with the pattern for rainy night driving. It is also observed that there is lower mental workload among the train drivers, which indicates that the train drivers are detached from their work.
4.Future research on manual lifting tasks in the automotive industry
Mirta Widia, Siti Zawiah Md Dawal and Nukman Yusoff
Malaysian Journal of Public Health Medicine 2016;16(Supplement 2):61-68
It is known that lifting tasks are one of the risk factors of musculoskeletal disorders in the automotive industry.
Extensive research has been carried out over the years to develop guidelines and determine safe limits in which an
individual can lift. For this reason, the objective of this study is to determine the significant risk factors of
musculoskeletal discomfort among manual lifting task workers in the automotive industry, and propose a
methodological framework for future research on manual lifting tasks. The subjects of this study comprise 211
manual material handling workers from the automotive industry. The subjects completed a set of questionnaires
which are used to elicit information on their demographic characteristics, as well as physical factors and the
prevalence of musculoskeletal discomfort. The Chi-Square test was used to determine the relationship between the
risk factors and musculoskeletal discomfort. The findings of the study show that the following postures (trunk bent
slightly forwards, hands above the knee level (p < 0.05), trunk twisted (over 45o) and bent sideways (p < 0.05) are
the significant risk factors of musculoskeletal discomfort among manual lifting task workers in the automotive
industry. A methodological framework on manual lifting task in the automotive industry is proposed based on the
findings of this study. The framework is developed based on the need to model human lifting capabilities so that task
demands can be designed to fit the workers’ capacity when performing lifting tasks.
5.Ablution Workstations Design For Person With Physical Disabilities In Malaysia
Siti Zawiah MD Dawal ; Mirta W ; Nur Syahirah A ; Muhammad Suhairi A
Malaysian Journal of Public Health Medicine 2020;20(Special 1):101-107
An investigation on ablution workstations design for person with disabilities has been carried out in this study. The focused were on wheelchair user or person with lower-limb impairment in Malaysia. The objective of this research is to determine the most suitable ablution workstation for person with disabilities. One hundred wheelchair users which include 74 males and 26 females participated in the study. The findings highlighted that the most suitable and preferred ablution workstation for person with disabilities is a separate design for washing hands and legs. The results also indicated that the noteworthy body parts that should be enhanced are arms, neck, trunk, and legs. Therefore, it can be concluded that it is important to design an ablution workstation with correct anthropometric dimensions referring to the population under investigation taking into account their preferences and disabilities limitation. Thus, the innovation will bring equality between people with disabilities and physically normal people in future facilities design. The workstation will become one of the worthy social contributions to the population of Muslim disabilities especially in Malaysia.