Age, Gender, and Muscle Strength: a Study Based on Indonesian Samples

Age and gender have been commonly used as a main criterion in accepting a job aplicant, but it is usually not clear how these affect job performance. While a number of recent studies have been done that describe the relationships between age, gender, and participants capacity (e.g., muscle strength), the results have been inconclusive. In Indonesia, in particular, such issues have been rarely investigated, and it is still important to study the issue since the relationships between these factors are population-specific. This study aimed at describing the relationships between age and muscle strength among workers for both genders. Ninety-six male and female workers (aged 18–65) were recruited in this study, and data on handgrip and lower back strength were collected. Findings of this study show that peak hand-grip strength occured at the age of around 35-40 years of age, regardless of gender. Maximum lower back strengh was identified at the age of 31-35 years old (for males) and 26-30 years old (for females). Comparisons between two extreme age groups (18-20 vs. 61-65 years of age) showed a mean strength decline of 50% for hand-grip and 30% for the lower back. For both protocols, female participants tended to have lower muscle strength (70-80% of their male counterparts). Findings of this study can be used as a basis in evaluating physical requirements of a job, and the corresponding factors (age and gender) relevant for the job

The Impact of Sleep Deprivation on the Level of Sleepiness, Fatigue, and Stress on Experiment Using Driving Simulator

Sleep prior to driving has been discussed widely in fatigue driving research focusing on how it affected driver on duty. This study is intended to compare the impact of prior normal sleep hour and sleep reduction during long-duration driving to subjective sleepiness, fatigue and stress level. To aim this objective, within-subject 2 x 2experiments was conducted (4 experiments condition). Sleep hour variable consists of ± 4 hours (var11) and ± 8 hours sleep (var12) before driving, and long duration driving consist of non-stop 5 hours driving (var21) ended with 60 minutes rest, and 2.5 hour driving x 2 sessions (var22) with 30 minutes break between session and ended with 30 minutes rest. Driving task conducted in laboratory started at ± 7 am to ± 1 pm using a simulator that set to highway and city route randomly. Thirteen participants were involved in these four experiments, each of them conducted in a different day in random fashion. Karolinska Sleepiness Scale (KSS/scale 1–9) and Visual Analogue Scale (0–10) were applied to rated subjective sleepiness and fatigue level, and saliva amylase was used to measure the participants’ stress level that was collected using Cocoro meter nipro. The result showed that sleepiness and fatigue level under sleep reduction condition was relatively higher compared to the normal sleep condition, while saliva amylase test result slightly increases after experiments, but cannot becategorized into stress condition yet. The conclusion is a duration and sleep hours before driving factors were induced fatigue, sleepiness and stress to driver, but lack of sleep has a higher impact compare to driving duration. Further research with another profession may give different results. Keywords: driving simulator, fatigue from driving, Karolinska Sleepiness Scale, sleep deprivation, stress leve

Fatigue evaluation in maintenance and assembly operations by digital human simulation

Virtual human techniques have been used a lot in industrial design in order to consider human factors and ergonomics as early as possible. The physical status (the physical capacity of virtual human) has been mostly treated as invariable in the current available human simulation tools, while indeed the physical capacity varies along time in an operation and the change of the physical capacity depends on the history of the work as well. Virtual Human Status is proposed in this paper in order to assess the difficulty of manual handling operations, especially from the physical perspective. The decrease of the physical capacity before and after an operation is used as an index to indicate the work difficulty. The reduction of physical strength is simulated in a theoretical approach on the basis of a fatigue model in which fatigue resistances of different muscle groups were regressed from 24 existing maximum endurance time (MET) models. A framework based on digital human modeling technique is established to realize the comparison of physical status. An assembly case in airplane assembly is simulated and analyzed under the framework. The endurance time and the decrease of the joint moment strengths are simulated. The experimental result in simulated operations under laboratory conditions confirms the feasibility of the theoretical approach

Sleep Deprevation Effect on the Driving Activity Using Sustained Attention Test

The rate of train accidents in Indonesia is still high, mainly caused by humans related to fatigue while on duty. One of the factors that influence the level of fatigue is the duration of the previous sleep time which causes the level of alertness at work to decrease. This study aims to determine how significantly a person alertness performance decreases due to sleep deprivation using Sustained Attention Test. The study was conducted with laboratory experiments using a train simulator involving twelve participants aged 21.2 ± 0.92 years. The independent variable is the duration of sleeping time before driving with a duration of eight hours for normal conditions and a duration of two hours for sleep deprivation. The dependent variable is the parameter on the Sustained Attention Test which is tested before and after driving using the Kruskal-Wallis test. The results showed that there was a increase in the value of the Sustained Attention Test, especially the error and miss parameters which were significant due to sleep deprivation with an average significance of p-value less than 0.05 and increasingly significant with an average of p-value less than 0.01 after driving activity. This shows that sleep deprivation greatly affects the drivers performance while on duty

Muscular load characterization during isometric shoulder abductions with varying force

This study sought to characterize muscle loading and fatigue during static shoulder abductions with varying force. In a supine posture, participants maintained fixed shoulder abductions against a time-varying external resistance, generated by a dynamometer-spring mechanism. Patterns (cumulative distribution) of the external resistance were varied by selecting different 10th and 90th percentiles of the distribution. Dynamometer angular velocities were also varied, to reflect different rates of cyclic muscle contraction. The degree of local fatigue development was assessed by common measures, including endurance time, strength reduction, and perceived discomfort. Myoelectric (EMG) signals were continuously obtained from the middle deltoid muscle throughout experimental exercise (60 min max). Changes in EMG root-mean-square (RMS) and spectral measures (derived from 1-s windows at peaks in the cyclic contractions) were used as manifestations of muscle fatigue. For each minute, the RMS signal was further reduced using two methods, the cumulative probability distribution of EMG (CPDE) and exposure variation analysis (EVA). The former resulted in three percentile values (10th, 50th, and 90th), whereas the latter method resulted in 10 different measures (grouped by EMG activity level and duration). A main finding of the study was the applicability of several common fatigue indicators for these cyclic, repetitive exertions. Overall, the use of CPDE and EVA to characterize task differences and predict muscle fatigue was found to have limited value. © 2007 Elsevier Ltd. All rights reserved

Kajian Ergonomi pada Alat dan Perlengkapan TNI dalam Rangka Mendukung Kepentingan Pertahanan Negara

This study purpose to determine the feasibility and ergonomics aspects of the P-1 and Ranpur Panser APS 1 6X6 produced by PT. Pindad. The data was collected using a survey method through filling out a questionnaire with a purposive sampling method, interviews, and observations. Questionnaires were distributed to 350 TNI soldiers for the use of the P-1 Pistol and 180 of the TNI soldier. Measurement of anthropometric data and fatigue of Ranpur Panser APS soldiers was carried out on 30 soldiers who were randomly drawn from 180 soldiers. The results showed that the Pistol P-1 produced by PT. Pindad in general was still safe, comfortable, and accurate to shoot. However, the addition of infrared will make it easier for soldiers to shoot the targets. The results of the research on the application of ergonomic aspects at Ranpur Panser APS 1 6X6 resulted in a value of 57.47% for the effective criteria, 66.83% for the safe criteria, 69.56% for the comfortable criteria, 75.83% for the healthy criteria, and 80.17% for the efficient criteria. The results show that Ranpur Panser APS fulfill overall EASNE aspects with several notes discussed. Related to the fatigue test, results obtained a significance value of 0.01<0.05 which indicates a significant correlation between fatigue before and after using Ranpur Panser APS 1 6X6

Psikososial dan Beban Kerja Perawat – sebuah Penelitian di Salah Satu RS Militer di Indonesia

This study aimed to determine the level of mental workload and psychosocial factors of nurses at the executive level in in-patient rooms of a military hospital. Data were collected by distributing questionnaires to 41 nurses who served in the in-patient rooms. Measurement of mental workload was carried out using the National Aeronautics and Space Administration - Task-Load Index (Nasa-TLX) questionnaire. Measurement of psychosocial factors was carried out using the Copenhagen Psychosocial Questionnaire (COPSOQ II) questionnaire. The results showed that the average value of the overall mental workload was in the high category. The value of psychosocial factors in the work environment shows good results on the majority of the rating scales. However, the hospital needed to pay attention to several factors, such as emotional demands, health perceptions, fatigue and stress and work pace. The results of this study also showed a strong and significant positive relationship between the dimensions of management's trust and performance &nbsp;with r=0.545(p=0.000). Thus, it is recommended that hospital management not only assess the performance of nurses, but also periodically assess mental workload and psychosocial factors in order to create a conducive work environmen

The Impact of Sleep Deprivation on the Level of Sleepiness, Fatigue, and Stress on Experiment Using Driving Simulator

Sleep prior to driving has been discussed widely in fatigue driving research focusing on how it affected driver on duty. This study is intended to compare the impact of prior normal sleep hour and sleep reduction during long-duration driving to subjective sleepiness, fatigue and stress level. To aim this objective, within-subject 2 x 2experiments was conducted (4 experiments condition). Sleep hour variable consists of ± 4 hours (var11) and ± 8 hours sleep (var12) before driving, and long duration driving consist of non-stop 5 hours driving (var21) ended with 60 minutes rest, and 2.5 hour driving x 2 sessions (var22) with 30 minutes break between session and ended with 30 minutes rest. Driving task conducted in laboratory started at ± 7 am to ± 1 pm using a simulator that set to highway and city route randomly. Thirteen participants were involved in these four experiments, each of them conducted in a different day in random Fashion. Karolinska Sleepiness Scale (KSS/scale 1–9) and Visual Analogue Scale (0–10) were applied to rated subjective sleepiness and fatigue level, and saliva amylase was used to measure the participants' stress level that was collected using Cocoro meter nipro. The result showed that sleepiness and fatigue level under sleep reduction condition was relatively higher compared to the normal sleep condition, while saliva amylase test result slightly increases after experiments, but cannot becategorized into stress condition yet. The conclusion is a duration and sleep hours before driving factors were induced fatigue, sleepiness and stress to driver, but lack of sleep has a higher impact compare to driving duration. Further research with another profession may give different results. Keywords: driving simulator, fatigue from driving, Karolinska Sleepiness Scale, sleep deprivation, stress leve