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.
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.
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.
Elderly are exposed to physical impairment. This has a strong impact on their daily activities including
frying, which is one of the most popular cuisine preparations. The stove height and work envelope
are two major ergonomic issues in performing cooking task. There has been little research focusing
on Malaysian elderly task performing in addressing these issues. The objectives of this study were to
identify the acceptable stove height and depth and to determine the working envelope among Malaysian
elderly using anthropometric data. A total of 55 Malaysian elderly (25 male and 30 female) aged between
60 to 85 years participated in this study. Five body measurements were taken from each subject using
an anthropometer. The measurements are stature height, shoulder height, arm span, arm reach forward
and waist height. Apart from these anthropometric measurements, their present stove height was also
measured. The acquisition of stove height dimensions was performed through a series of door to door
visit of the elderly homes in Kg. Sg. Merab. These variables were used to estimate the elderly working
envelope and determine the stove height, width and depth. Data were analysed using SPSS software. The
waist height dimension was to estimate the stove height, the arm reach forward for the depth and the arm
span for the length of the table-top where the stove was placed. Meanwhile the stature and shoulder height
were used for estimating the position of the overhead compartment or placement of cooking utensils.
The 5
th
percentile was chosen since it is appropriate to accommodate 90% of the studied population. The 5
th
percentile was also applied for the setting
of the working envelope so as to provide better
reaching tolerances. Meanwhile, standard was used
to compare the present state of the studied kitchen
setting. The results show that 56.4% of the elderly
waist height is lower than the standard table-top
height which is 36 inches (91.4cm) and 36.4% of the stove height was found higher than that of the standard. This could apparently cause fatigue and
discomfort to shoulders, the neck, the arm and the back of the user. Anthropometrics measurements can
be used for estimating the stove height, length and depth. These could also calculate a space taken for
certain physical activities, such as frying task envelope. Providing a good combination of stove height,
length, depth and ergonomic working envelope could hopefully improve the elderly cooking task and
increase their quality of life.
Ergonomics is generally to design for human use and optimizing the working and living conditions. The comfort, safety and ease of use of systems, products and machines require the principles of ergonomics to be incorporated into the design. Anthropometry is a part of ergonomics which deals with the measurement of body dimensions, its capability and limitations of the human ability. Studies have indicated that body dimensions differ for various populations, depending on ethnic group, sex and age. The measurement of physical characteristics and abilities of people provides information that is essential for the appropriate design of occupational and non- occupational environments, as well as for the design of consumer products, clothing, tools and equipment. It has been considered as the very basic core of ergonomics in an attempt to resolve the dilemma of 'fitting people to machines'. It has also been regarded as a branch of anthropology which deals with physical characteristics of the man in time and space, particularly with individual variation, ontogenesis and generic development. Knowledge about man from the point of view of physical anthropometry is very useful for the purpose of ergonomics and design. Thus it is important that an anthropometric database for each nation is developed to ensure design of products and systems are compatible with the user population. In Malaysia, many researchers have conducted anthropometric studies on various groups of people, focused on a small sample size and used for specific designs. Unfortunately, the measurements are not representatives of the population. The work has been individually based, confined to certain group of researchers in various universities and there is no concerted effort towards developing a national anthropometric database.This paper discusses some of the anthropometry work conducted in Malaysia, the problems and challenges in developing the national database, the importance of anthropometry and the roles that the government has to play in developing the database.
Congenital talipes equinovarus (CTEV) or clubfoot is a complex deformity of the foot that is characterised by four main deformities; forefoot cavus and adductus, hindfoot varus and ankle equinus. Currently, the Ponseti method is the most general and recognized treatment with a high success rate of over 90%. The treatment involves gentle manipulation and serial casting. However, the casting method could create complications for the patients such as soft-tissue damage and inconvenience in following the treatment schedule especially for those living far away from hospital. The aim of this research is to develop an adjustable corrective device for clubfoot treatment based on the techniques in the Ponseti method and at the same time attempt to eliminate the side-effects. The prototype consists of six adjustable movements from six different mechanisms to correct the four deformities. The prototype was developed using 3D printing method and the main material used is polylactic acid (PLA), rubber, aluminium and cotton fabric with sponge. The total weight of the prototype is around 300 g.
Manual Material Handling (MMH) involves lifting, bending, and twisting motions of the torso. Poor
lifting technique is often considered a major risk factor in low back injury associated with manual lifting
tasks. Currently, there is little work on the effects of lifting on the Malaysian population. The MMH
activities that was designed with the different lifting heights, frequency, weight of loads and the effect
on of biceps and triceps muscle contraction of the subjects during the lifting tasks were studied. The
parameters involved are weight of the loads lifted, height of the loads lifted and lifting frequency as the
independent variables. Whereas the dependent variable is Electromyography (EMG) signal. The weight
loads are varying from 10kg up to 24kg and the heights of the loads travels from the floor to 70cm
and 130cm heights. The frequency of lifting is set to 1 lift and 6 lifts per minute. 14 healthy male and
female subjects were recruited in this study. The questionnaires and consent form were used to identify
the health condition of the subjects before performing the lifting tasks. The EMG activity was recorded
and collected from biceps and triceps muscles using the Shimmer EMG system. This method is used
in determining the maximum acceptable weight limit (MAWL) that can be lifted by the subjects in the
lifting tasks. This research aims to design a lifting equation that suits for Malaysian people. Therefore,
the effects of different manual lifting tasks on Malaysian physiological limits need to be identified.