Hilma Raimona Zadry

Anthropometric Database for the Learning Environment of High School and University Students

Abstract This paper presents an anthropometric database of high school and university students from Kuala Lumpur, Malaysia. Forty-one high school participants (21 males and 20 females), 13–17 years old, and 143 university students (74 males and 69 females) took part in the study. Twenty-one static body dimensions were measured. The greatest mean differences in the anthropometric data between male and female high school students were found in the sitting elbow height. In addition, a comparison of anthropometric data of male and female university students showed that data for males and females were significantly different, except for buttock–popliteal length, sitting elbow height and thigh clearance. The primary aim of this study was to develop an anthropo-metric database that could be used as a primary reference in designing products, devices and equipment for ergonomic learning environments.

The Relation Between Upper Limb Muscle and Brain Activity in Two Precision Levels of Repetitive Light Tasks

A study was conducted to investigate the effects of repetitive light tasks of low and high precision on upper limb muscles and brain activities. Surface electromyography (EMG) and electroencephalography (EEG) were used to measure the muscle and brain activity of 10 subjects. The results show that the root-meansquare (RMS) and mean power frquency (MPF) of the muscle activity and the mean power of the EEG alpha bands were higher on the high-precision task than on the low-precision one. There was also a high and significant correlation between upper limb muscle and brain activity during the tasks. The longer the time and the more precise the task, the more the subjects become fatigued both physically and mentally. Thus, these results could be potentially useful in managing fatigue, especially fatique related to muscle and mental workload.

Investigation of upper limb muscle and brain activities on light assembly tasks: A pilot study

A study was conducted to investigate the effect of light assembly task on upper limb muscles (biceps brachii and upper trapezius) and brain activities. The task was conducted in two levels of time pressure (No time-stress and time-stress levels). Each task was done for one hour experiment. Surface electromyography (SEMG) measured upper limb muscle activities from six subjects. The results indicated that the biceps brachii and upper trapezius activities tend to increase as the increase of time. It indicated muscle fatigue. Electroencephalography (EEG) was simultaneously recorded with SEMG to record brain activities from Fz, Pz, O1 and O2 channels. EEG alphas RMS were higher on the task with time-stress than task without time-stress. The significant correlation was found between SEMG RMS and EEG alpha RMS. Thus, there was relation between upper limb muscle and brain activity while doing the light assembly task.

Investigation of upper limb muscle activity during repetitive light task using surface electromyography (SEMG)

A study was conducted to investigate the effect of upper limb muscles during repetitive task consisted of three hand-arm directions: 30°, 90°, and 150°. The aims of this study were to investigate muscle activity during repetitive task, to compare muscle activity between genders and to determine the correlation between muscles and time. Biceps brachii, anterior deltoid, and upper trapezius muscles were identified as a significant muscle in the repetitive light task experiment. Surface electromyography (SEMG) measurements for each muscle mentioned above were taken from ten subjects in the duration of one hour experiment. The results indicated that anterior deltoid is the highest affected muscle by the tasks. There was a significantly increase of root mean square (RMS) between the beginning and the end of the experiment, that indicated muscle fatigue. However there were no significant differences of RMS between male and female subjects, and between 30°, 90°, and 150° hand-arm directions.

Development of statistical models for predicting muscle and mental activities during repetitive precision tasks

This study was conducted to develop muscle and mental activities on repetitive precision tasks. A laboratory experiment was used to address the objectives. Surface electromyography was used to measure muscle activities from eight upper limb muscles, while electroencephalography recorded mental activities from six channels. Fourteen university students participated in the study. The results show that muscle and mental activities increase for all tasks, indicating the occurrence of muscle and mental fatigue. A linear relationship between muscle activity, mental activity and time was found while subjects were performing the task. Thus, models were developed using those variables. The models were found valid after validation using other students’ and workers’ data. Findings from this study can contribute as a reference for future studies investigating muscle and mental activity and can be applied in industry as guidelines to manage muscle and mental fatigue, especially to manage job schedules and rotation.

Incorporating Ergonomics Evaluation in Assembly and Disassembly of Repetitive Task: Focusing on Load Task

Human performance seems to be neglected in the design of assembly and disassembly of a product despite the increasing awareness among people on green environmental issues. Incorporating an ergonomics evaluation can be considered as an alternative empirical solution to tackle the issue efficiently. Therefore, the objective of this study is to investigate human performance with reference to muscle activity while performing assembly and disassembly of manual tasks focusing on load variability. Upper limb muscle activities were investigated in this study. Twenty participants were asked to perform assembly and disassembly of selected tasks at two load-levels. The results of this study indicated that load tasks affect human performance. The findings from this study highlighted that the muscle activity for the medium load task was prone to fatigue faster than the low load task (28.19% in average). Thus the study has revealed the importance of incorporating the ergonomics principle solution in the design of assembly and disassembly tasks to increase human performance.

Ergonomics intervention on an alternative design of a spinal board.

A spinal board is the evacuation tool of first aid to help the injured spinal cord. The existing spinal board has several weaknesses, both in terms of user comfort and the effectiveness and efficiency of the evacuation process. This study designs an ergonomic spinal board using the quality function deployment approach. A preliminary survey was conducted through direct observation and interviews with volunteers from the Indonesian Red Cross. Data gathered were translated into a questionnaire and answered by 47 participants in West Sumatra. The results indicate that the selection of materials, the application of strap systems as well as the addition of features are very important in designing an ergonomic spinal board. The data were used in designing an ergonomic spinal board. The use of anthropometric data ensures that this product can accommodate safety and comfort when immobilized, as well as the flexibility and speed of the rescue evacuation process.

Investigation of Customer and Technical Requirements for Designing an Ergonomics Notebook Soft Case Using Quality Function Deployment (QFD) Approach

Notebook experienced rapid growth following the human needs. This is evidenced by the increase of notebook sales every year. The problem of shortage and mismatch facilities and supporting infrastructure causes of notebook users force their capacity to use the notebook with non ergonomic position. A preliminary survey through interviews found that the notebook soft case not yet provide ease of mobilization, convenience of use, and protection of health to the users. Therefore it is required an alternatives design of notebook soft case which is ergonomics and multifunction. One of the methods used to design the notebook soft case is Quality Function Deployment (QFD). In this study, QFD is implemented to determine the customer and technical requirements. The results indicate that the material selection which has impact resistant and waterproof is very important to design an ergonomics and multifunctional notebook soft case.

The Prevalence of Muscle Fatigue Symptoms in Industries at Lembah Klang Malaysia

The purpose of this study was to investigate the prevalence of muscle fatigue symptoms and its relation to the job demands among industrial workers with repetitive light tasks. The participants were one hundred and sixty seven workers from the manufacturing and electronics industries in Lembah Klang Malaysia. The results show that the prevalence of muscle fatigue symptoms is high among industrial workers in the manufacturing and electronics sectors. The highest prevalence was for the shoulder (70.659%) and neck (65.269%). The prevalence of muscle fatigue symptoms were found to be higher for females than males. The higher prevalence of muscle fatigue symptoms are found to be related to job demand factors, particularly monotonous, attention requirement, precision, and repetitiveness.

Upper Limb Muscle and Brain Activity in Light Assembly Task on Different Load Levels

A study was conducted to investigate the effect of load on upper limb muscles and brain activities in light assembly task. The task was conducted at two levels of load (Low and high). Surface electromyography (EMG) was used to measure upper limb muscle activities of twenty subjects. Electroencephalography (EEG) was simultaneously recorded with EMG to record brain activities from Fz, Pz, O1 and O2 channels. The EMG Mean Power Frequency (MPF) of the right brachioradialis and the left upper trapezius activities were higher on the high‐load task compared to low‐load task. The EMG MPF values also decrease as time increases, that reflects muscle fatigue. Mean power of the EEG alpha bands for the Fz‐Pz channels were found to be higher on the high‐load task compared to low‐load task, while for the O1–O2 channels, they were higher on the low‐load task than on the high‐load task. These results indicated that the load levels effect the upper limb muscle and brain activities. The high‐load task will increase muscle a...