The Effect of Work Posture on Work Fatigue in the Metal Moulding Department of XYZ Company
Rifki Apriliansyah1*, Muhammad Ragil Suryoputro1
1 Faculty of Industrial Technology, Universitas Islam Indonesia, Yogyakarta, Indonesia
*Corresponding Author: [email protected]
Accepted: 15 August 2022 | Published: 1 September 2022
DOI:https://doi.org/10.55057/ijbtm.2022.4.3.12
__________________________________________________________________________________________
Abstract: One of the things that can cause a work accident is manual material handling (MMH). Manual material handling activities are still often found in modern industries because MMH activities are easy to apply, cheap, and very flexible to do. The poor manual activity of material handling can lead to musculoskeletal complaints, spinal cord injuries, and work fatigue. If the worker does his job with a work posture that is not ergonomic then the worker will be vulnerable to work fatigue. Work posture problems and work fatigue are also experienced in XYZ Company which is one of the companies engaged in the metal casting industry. Therefore, the study aimed to examine the effect of work posture on the level of work fatigue in the metal moulding department of XYZ Company using NBM questionnaires, SOFI questionnaires, and REBA methods. The results showed that the segment of the body most felt pain by the operator was the left leg. Wherefrom the results of identification of working posture there is one operator who gets a REBA score of 10 and three operators who get a REBA score of 12. Then, the level of work fatigue from the four operators, namely, amounted to 3.46; 3.21;
2.7; and 3.02. The four values have a value that is in the SOFI score range of 1.13-4.87 which means all four operators experience moderate work fatigue. Then a regression test was conducted to determine the effect of both variables and obtained a correlation coefficient (r) value of 0.754; and a coefficient of determination (R Square) of 0.569. These values show the effect of work posture on work fatigue has a strong relationship and an effect of 56.9%.
Keywords: Metal casting industry, NBM Questionnaire, REBA Method, SOFI Questionnaire ___________________________________________________________________________
1. Introduction
The industrial sector can’t be separated from the problems due to work accidents. This is shown by the International Labor Organization (ILO), there are 2.78 million cases of workers dying per year, with details of 2.4 million deaths due to occupational diseases and 380 thousand deaths due to work accidents (Salcha, M. A, et al., 2020). In Indonesia, in 2019 there were 114,235 cases, then increased in 2020 to 177,161 cases of work accidents (BPJS, 2021). From these data, we can know that the number of work accidents in Indonesia is still relatively high.
One of the things that can cause a work accident is manual material handling (MMH). MMH activity is still often found in modern industries because MMH activities are easy to apply, cheap, and very flexible to do (Suhardi, 2008). However, if MMH activity is done un ergonomically it can cause damage to body tissue caused by excessive lifting weights
(Nurmianto, 2004). The poor manual activity of material handling can lead to musculoskeletal complaints, spinal cord injuries, and work fatigue (Zen &Zamora, 2016).
Work fatigue describes the body's response to the activities performed and the exposure received during work (Gaol, et, al., 2018). Work fatigue that is not overcome in do not long can become chronic fatigue felt before, moderate, and after work (Suma'mur, 2009). If the worker continues to do his work when he is feeling work fatigue, it will increase the possibility of a work accident. According to Suhisono (2012), if the worker does his job with a work posture that is not ergonomic, he will be vulnerable to work fatigue.
Work posture is the determining point in analyzing the effectiveness of a job. The work done by the operator is good and ergonomic then it can be ascertained that the results obtained by the operator will be good. However, if the operator's working posture is not ergonomic then the operator will be easily exhausted. If the operator is easily exhausted then the results of the work done by the operator will also decrease and not by expected (Sulaiman & Sari, 2018). In work, if we do a work posture that is not ergonomic it can cause MSD's, which is muscle strengthening for workers who do the same and continuous movements (Tayyari & Smith, 1997).
Therefore, it is necessary to do further research related to the effect of work posture on work fatigue in companies that implement manual material handling activities. To find out the work posture, initial identification can be done using the Nordic Body Map (NBM) questionnaire to find out the complaints felt in the body segments. Then it can be identified and further analyzed using the Rapid Entire Body Assessment (REBA), Rapid Upper Limb Assessment (RULA), or Quick Exposure Check (QEC) methods, where these methods have their respective focuses and are adapted to the work being carried out. For identification and analysis of work fatigue, it can be done using the Industrial Fatigue Research Committee (IRFC) questionnaire or the Swedish Occupational Fatigue Inventory (SOFI) questionnaire. Then to determine the effect of the two variables can use a regression test.
The company that will be studied in this research is XYZ Company. XYZ Company is a national private company engaged in metal casting and machining located in Ceper, Klaten.
The production process at XYZ Company includes pattern making, molding, metal smelting, pouring molten metal into molds, cooling and freezing, mold demolition, cleaning and inspection of casts, and then cast products are completed. This research will focus on the XYZ Company molding department. It’s caused by the existing data being limited and difficult in accessing.
Based on a preliminary survey conducted by Rahmawati, et al. (2020), pulse rate measurements were carried out for 10 workers at XYZ Company, 30% of the workers experienced a light workload, 50% of the workers experienced a moderate workload, and 20% of the workers experienced a rather heavy workload. Then, based on the observations of workers in XYZ Company molding parts related to work fatigue, workers feel complaints such as weakness, drowsiness, lethargy, and pain in some parts, where the condition can be a sign of workers experiencing work fatigue. In the interview, workers complained of pain in the shoulders, back, and legs. The complaint is caused by the process of working the molding part is done by lifting, lowering, and squatting repeatedly and carried by carrying a load on the pour bucket.
Such complaints if not followed up will result in musculoskeletal disorders. If this happens, it can result in decreased work performance and impact on the decline in company productivity.
Based on the above problems, XYZ Company needs to pay attention to the working posture of manual material handling activities and the level of work fatigue experienced by its workers in the molding department. To analyze the risks of working posture researchers will make initial observations using the Nordic Body Map (NBM) questionnaire to identify complaints felt by workers in some parts of their bodies (Wilson, 1995). Next, it will be analyzed working posture using the Rapid Entire Body Assessment (REBA) method. Then, from the analysis of the work posture will be seen whether or not it has a relationship with work fatigue felt by workers. To analyze work fatigue, the Swedish Occupational Fatigue Inventory (SOFI) questionnaire was used. The results of work posture analysis and work fatigue obtained will be the basis for the recommendations that will be given to XYZ Company to improve the work system in the production process.
2. Literature Review 2.1 Work Posture
Work posture is the position of the worker's body when doing work activities that are usually related to work area design and task recruitment (Pulat, 1992). Work posture is the determining point in analyzing the effectiveness of a job. If the working posture carried out by the operator is good and ergonomic then it can be ascertained that the results obtained by the operator will be good. However, if the operator's working posture is not ergonomic then the operator will be easily exhausted so that it will experience an unexpected decrease in performance (Susihono, 2012). According to Patradhiani et al. (2019), improper working positions such as sitting positions will potentially cause injury to the body part of the back, while for a long period worker are positioned standing it can cause muscle tension and limb fatigue so that it can cause errors in the musculoskeletal system.
2.2 Determination of Body Segment Complaints Due to Work
Nordic Body Map is one of the measurement questionnaires to measure workers' muscle pain (Wilson and Corlett, 1995). Pain measurements are obtained from questionnaires presented in the form of checklists. This questionnaire uses a successful approach to find out the part of the body that experiences complaints from pain to very painful. This questionnaire also uses images of the human body that are divided into 9 main parts, namely the neck, shoulders, upper back, elbows, lower back, waist, knees, and heels.
In the NBM questionnaire there are levels of complaints classified with codes A, B, C, and D.
Where level A means no pain and is worth 1. Level B means quite sick and is worth 2. For level C means painful and is worth 3. Then, level D means very painful and is worth 4.
2.3 Work Posture Measurement
Rapid Entire Body Assessment (REBA) is a method that assesses the posture risk of the entire worker's body influenced by coupling factors, weights sustained by the body, and worker activity. This REBA method can be used quickly to assess the posture of a worker, in addition to being influenced by coupling factors, as well as external loads supported by the body and worker's activity (Prabaswari et al., 2020). REBA is used quickly to assess a worker's posture.
The input used in the REBA method is the retrieval of worker posture data using photos, determination of angles on the body, neck, legs, upper arms, forearms, and wrists (Rahayu, 2020). REBA is also a method for assessing occupational risks associated with spinal cord injuries. The REBA method is usually used for dynamic or repetitive work. Assessments using REBA have been conducted by Dr. Sue Hignett and Dr.Lynn McAtamney in the journal through the following stages:
1) Stage 1: Retrieving worker posture data using the help of videos or photos.
2) Stage 2: Determination of the corners of the worker's body parts.
3) Stage 3: Determination of the weight of the objects lifted, coupling, and activities of workers.
4) Stage 4: Calculation of REBA values for the posture in question.
The following is a questionnaire that can be used to calculate work posture using the Rapid Entire Body Assessment (REBA) method.
Figure 1: Rapid Entire Body Assessment Questionnaire Source: ergoplus.com
2.4 Work Fatigue
Work fatigue describes the entire body's response to the activities performed and the exposure received during work. When the body performs activities during 8 hours of work, the body will be prone to fatigue. The body that experiences fatigue will appear symptoms such as frequent yawning, thirst, drowsiness, and difficulty concentrating. There are three indications of work fatigue, namely weakening of activity, weakening of work motivation, and physical fatigue.
These three indications are symptoms that can be observed to find out work fatigue (Gaol, et, al., 2018).
If work fatigue is not immediately addressed and immediately rested, there will be an accumulation of fatigue in a day, so it can have a more severe impact on health. According to Tarwaka (2010), the risk of work fatigue is work motivation decreases, low performance, low work quality, many mistakes, low work productivity, stress due to work, occupational diseases, injuries, and work accidents. Meanwhile, according to Setyawati (2010), the impact of work fatigue is decreased work performance, the body feels bad, morale decreases, and decreases work productivity. The types of work fatigue are as follows.
1) Muscle fatigue, the phenomenon of reduced muscle performance after physical stress for a time is called physiological muscle fatigue, which is indicated not only by reduced physical stress but also by lower movement.
2) General fatigue, is an overwhelming feeling of fatigue. All activities become disrupted and will usually cause drowsiness.
2.5 Work Fatigue Measurement
The SOFI (Swedish Occupational Fatigue Index) questionnaire is used to measure work fatigue from the subjective side. The SOFI (Swedish Occupational Fatigue Index) questionnaire consists of 5 dimensions which are Lack of Energy, Physical Exertion, Physical Discomfort, Lack of motivation, and Sleepiness. Of the 5 dimensions, there are 25 question points, with an assessment from a scale of 0 to 6 with an interpretation of the value of 0 because the question is not felt at all, while 6 means that the question is felt by the respondent for each point owned by each dimension, while for one dimension as a whole the value (score) 0 means not felt at all and the value (score) 30 means very felt by the respondent (Primary). Et. al., 2014).
3. Result and Discussion
In this study, the research subjects were 4 workers, from a total of 8 workers in the Moulding section, male with an age range of 40-60 years who carried out the process of printing liquid metal into moulds. The following are the operators in this study.
Table 1: Research Subject in This Study
Operator Age
(Year) Gender Weight
(Kg) Department Disease History
Operator 1 52 Male 62 Moulding -
Operator 2 43 Male 56 Moulding -
Operator 3 40 Male 51 Moulding -
Operator 4 50 Male 53 Moulding -
Based on the research conducted, the results of the Nordic Body Map (NBM) questionnaire of operators 1 to 4 are known that the 5 body parts that have the highest total NBM value in a row are the left leg body segments, waist, left ankle, right ankle, left calf. The results of all segments of the body can be seen in the Figure 2 below.
Figure 2: Nordic Body Map Operator Questionnaire Results
Pain in this segment of the body is felt due to the presence of an unsanctioned daily work position with an abnormal operator work posture that causes complaints on the operator's body.
This can be dangerous for the operator's body because such complaints can cause muscle pain, joint pain, even damage to the muscles.
Once known body segments that often experience complaints, it is used as a reference to identify working posture with the REBA method. Here is the angle of the working posture that is formed while the operator is at work.
Figure 3: Identification Results of Working Posture Angle
In the analysis of the working posture of the REBA method, there are 6 points that are used as references to form angles on the operator's body, namely, neck, shoulders, elbows, wrists, waist, and knees. In Figures 4.7 to 4.10 there is a blue line which is a connecting line from the six reference points, then the yellow line indicates the normal axis of the body. After the reference points are connected, 6 angles are obtained which are marked with the letters A, B, C, D, E and F. The following is an elaboration of the six angles formed.
1) Angle A, is the angle between the operator's neck posture when working with a normal neck posture.
2) Angle B, is the angle between the operator's upper arm posture while working with the normal upper arm posture.
3) Angle C, is the angle between the operator's forearm posture while working with the normal forearm posture.
4) Angle D, is the angle between the operator's back when working with a normal back posture.
5) Angle E, is the angle between the operator's wrist posture when working with normal wrist posture.
6) Angle F, is the angle between the operator's foot posture when working with normal foot posture.
The following is a recapitulation of the six angles formed by the operator when working, which can be seen in Table 2 below.
Table 2: Overall Operator Posture Angle
Angle
Code Angle Segment Operator 1 Operator 2 Operator 3 Operator 4
A Neck 21,76° 39,89° 24,24° 19,90°
B Upper Arm 55,56° 50,65° 56,89° 81,04°
C Forearm 86,60° 76,97° 71,39° 39,57°
D Back 48,73° 24,06° 26,65° 32,76°
E Wrist 12,03° 32,45° 34,83° 52,54°
F Foot 26° 62,14° 33,62° 74,68°
Then, the six angles formed were processed using Ergofellow 3.0 software to get them working posture value of the REBA method as follows.
Table 3: REBA Score Results
Operator REBA
Score Risk Level Action
Operator 1 10 High Risk Investigations need to be carried out and changes must be made Operator 2 12 Very High Risk Changes must be made Operator 3 12 Very High Risk Changes must be made Operator 4 12 Very High Risk Changes must be made
The REBA score from three operators is worth 12 and one operator is worth 10. For REBA score 12 belongs to the category of very high risk where follow-up is necessary to change is needed. Meanwhile, for REBA score 10 belongs to the category of high risk where follow-up is necessary to be investigated and can be applied changes. If the working posture carried out by the operator of the XYZ company molding department is not repaired immediately will have an impact on the injury to the nervous system or musculoskeletal disorders characterized by injuries to muscles, tendons, ligaments, nerves, joints, cartilage, bones or blood vessels in the hands, feet, head, neck, or back (Eko, 2003).
Poor working posture in addition to causing complaints in the musculoskeletal system can also cause work fatigue (Zen &Zamora, 2016). Furthermore, it is carried out to be done with the SOFI questionnaire. The following is a calculation of the Swedish Occupational Fatigue Inventory (SOFI) average work fatigue value from the four operators which can be seen in Table 4 below.
Table 4: Recapitulation of Average SOFI Questionnaire Data
Dimension Aspect Scale Total
Scale Average 0 1 2 3 4 5 6
Lack of Energy
Overwork - 1 - 3 - - - 10
3 Feel tired - - - - 2 2 - 18
Energy drained to
do other things - 1 - 2 1 - - 11 Feeling a lot less
energy - - 1 - 2 1 - 15 Excess energy after
work 1 - 3 - - - - 6
Physical Activity
Sweating - - - 1 1 1 1 18
3,2 Breathe heavily - - - 2 2 - - 14
Feel the heart
pounding - - - 4 - - - 12 Body feels warm - - - 3 1 - - 13 Out of breath 1 1 - 2 - - - 7
Physical Discomfort
Feel the muscles
tighten - - - - 1 2 1 20
4,4375 Feeling stiff in the
joints - - 1 - - 2 1 18 Numbness/cramping
at some point - 1 - - 1 1 1 16 Feeling pain at
some point - - - 1 1 2 17
Lack of Motivation
Not interested in the
surroundings - 1 2 1 - - - 8
2,25 Not moving
much/passive - 2 2 - - - - 6 Feeling sluggish - 2 - 1 - 1 - 10
Feeling less
concerned - 2 - - 1 - 1 12
Sleepiness
Sleepy 0 0 1 - 1 2 - 16
2,6 Fall asleep 1 2 1 - - - - 4
Blurred vision due
to sleep - - 3 - - 1 - 11 Frequent yawning - 1 2 - 1 - - 9 Feeling lazy to do
something - 1 2 1 - - 12
Work Fatigue Score 3,098
The work fatigue value of the four operators moulding department of XYZ Company can be seen in Table 5 below.
Table 5: SOFI Score Results
Dimension Operator 1 Operator 2 Operator 3 Operator 4
Lack of energy 3,2 3 2,4 3,4
Physical Activity 3 3,4 3 3,4
Physical Discomfort 4,25 5,75 3,25 4,5
Lack of Motivation 3,25 1,5 2,25 2
Sleepiness 3,6 2,4 2,6 1,8
Total 3,46 3,21 2,7 3,02
Of the five dimensions on the SOFI questionnaire, physical discomfort became the dimension that had the highest average work fatigue value with a work fatigue score of 4,438. In the dimension of physical discomfort, there are 4 aspects of the question, namely, feeling stiff muscles, feeling stiff in the joints, numbness/cramping at some point, and feeling pain at some point. If associated with the NBM questionnaire has, complaints of physical discomfort felt such as cramps in the calf, stiffening muscles in the left leg, then pain in the back. Based on research Umyati et al., (2020), workers who feel work fatigue such as aches in the legs, knees, back, hands, shoulders, and head can be caused by work done with a work posture that is not ergonomic for a long time such as bending and squatting due to workers' activities in repairing damage to machine parts. There is no seating around the production machine for workers to unwind. So, when workers feel tired, they will sit around the machine. In addition, the condition of the workshop area is hot, and humid which can add to the fatigue factor of workers when doing activities.
A simple linear regression test is used to see the extent of the effect of variable working posture on work fatigue.
Table 6: Normality Test Results One-Sample Kolmogorov-Smirnov Test
Unstandardized Residual
N 4
Asymp. Sig. (2-tailed) 0.161
Parameter 0.05
Description Ho accepted
From the results of the normality test, obtained the value of Asymp Sig. (2-tailed) of 0.161 which means the result of significance meets the decision that the sig value. >0.05 states H0 is accepted and H1 is rejected, meaning work posture and work fatigue data are normally distributed so that the data can proceed to the next test.
Table 7: Regression Test Coefficient Results Coefficients
Model t Sig. Parameter Description Work Posture -1.624 .246 0,05 Ho accepted
The results of the simple linear regression test obtained a correlation coefficient (R) value of 0.754 and a coefficient of determination (R Square) of 0.569. From these values, it can be concluded that the working posture variable and the work fatigue rate variable have a correlation coefficient of 0.754 which means the correlation of both variables is strong. For the
effect rate variable X (work posture) affects variable Y (work fatigue rate) is by 56.9% which means the effect of the working posture is significant.
Based on the results of the analysis of NBM questionnaires, REBA methods, and SOFI questionnaires, the recommendations that can be given to the operator molding XYZ Company to minimize the risk of occurrence of work posture that is not ergonomic and the birth of work on the operator's body is as follows:
A. Personal Protective Equipment 1) Safety Helmet
Figure 4: Safety Helmet
Safety Helmet type 1 and class C, which according to ANSI /ISEA Z89.1-2014, can be used to protect the head from dangers coming from the upper direction such as the fall of objects.
It is also classified as class C and is designed to protect the head from falling objects but not for electric shocks or corrosive materials.
2) Hand Glove
Figure 5: Hand Glove
This type of A6 glove, which according to ANSI/ISEA 105-2016, can be used for jobs with the potential danger of being exposed to high cuts, metal recycling, metal fabrication, sharp metal stamping, recycling processes, and metal manufacturing.
3) Safety Shoes
Figure 6: Safety Shoes
SBP-grade safety shoes with WRU features, which according to EN ISO 20345:2011, are equipped with basic pounding resistant toe protection, oil-resistant outer soles, and have sharp object penetration resistance at mid-sole. Then the top is made of a material that is resistant to penetration by foreign bodies and water absorption.
B. Administrative Control 1) Schedule short-term breaks.
Scheduling a short-term rest system in between jobs can be called a white-collar. Scheduling breaks can be as long as 10 minutes every 1 hour. This is useful for reducing the impact of a marked workload from an increased pulse and reducing the impact of operator work fatigue.
2) Conduct Training in Occupational Safety and Health (OSH).
Training can be in the form of providing information and understanding of how to work in good, safe, and comfortable conditions. With the training of OSH, it is expected that workers can better understand working procedures that are not only safe but also comfortable.
3) Exercise the moment before the worker starts his job.
The company can hold hours of light exercise at the moment before the work begins which can be in the form of stretching to train the muscles so as not to stiffen. This can be reinforced based on Dreisinger (2014) who says that exercise is an important strategy for the management of back pain.
C. Engineering Controls
1) Redesign the workings of the workers.
Proposed improvements that can be applied related to the operator's working posture are to minimize movement or abnormal posture and strive to follow a neutral posture (Mariawati, 2013).
2) Redesign the pour bucket.
It is necessary to redesign the pour bucket to have a good coupling factor value, which means the type of handle is strong and right in the middle of the side of the load. One way that can be done redesigning the pour bucket is by paying attention to the anthropometric aspects of workers. By paying attention to anthropometric aspects, the tool will be adjusted to the dimensions of the operator's body so that it is more comfortable to use.
Figure 7: Bucket Pour Proposal
3) Redesigning the workstation on the molding department
Figure 8: Redesigning the Workstation
Redesign of workstations can be initiated using the 6S. 6S method is the key to designing efficient workplaces, reducing waste, and optimizing quality and productivity through organized environmental monitoring and maintaining an environment safe from accidents (Gautam et al., 2014). By applying 6S to the molding department, XYZ Company will know what items are needed and not needed at the work station, so that the work station becomes more organized. According to Dhounchak (2017), more organized workstations can increase the productivity of the company. Redesigning the workstation can also be done by providing a special place for workers to pour metal liquid into the pour bucket so that the operator's posture does not need to bend too much. Then at the work station, it can also be given a safe and arranged transportation line. So that there is a special path for workers that can be used to perform manual material handling activities.
4. Conclusion
The conclusions that can be made based on the result and analysis of the effect of work posture on the level of work fatigue are. For worker posture molding department analyzed using NBM questionnaire and REBA method. Results from the NBM questionnaire showed that the segment of the body most felt pain by the operator was the left leg. In general, the results of the NBM questionnaire showed that the body segments that are often felt by the operator experiencing complaints are the left body segment and the back body. For the results of the REBA method, there is one operator that gets a REBA score of 10 and there are three operators who get a REBA score of 12. For REBA score 10 belongs to the category of high risk where follow-up is necessary to be investigated and can be applied changes. Meanwhile, for REBA score 12 belongs to the category of very high risk where follow-up is necessary to change is needed.
For the level of work fatigue, the molding department workers were analyzed using the SOFI questionnaire. The results of the SOFI questionnaire from the four operators i.e., operator 1 has a SOFI score of 3.46; operator 2 of 3.21; operator 3 of 2.7; Operator 4 is 3.02. The four values have a value that is in the SOFI score range of 1.13-4.87 which means that all four operators experience moderate work fatigue while doing their work.
The effect of work posture on work fatigue was tested using a linear regression test. From the results of a simple linear regression test obtained a negative value of 0.246; a correlation coefficient (r) level of 0.754; and the coefficient of determination (R Square) is 0.569. These values show that the effect of work posture on work fatigue has a strong relationship and an effect of 56.9%. The recommendations refer to the Hierarchy of Controls, which focuses only on personal protective equipment, administrative control, and engineering controls.
References
BPJS Ketenagakerjaan. (2021). Jumlah Kecelakaan Kerja di Indonesia Masih Relatif Tinggi.
(Online): https://www.bpjsketenagakerjaan.go.id/ (25 Oktober 2021).
Eko, N. (2003). Ergonomi Konsep Dasar dan Aplikasi. Surabaya. Prima Printing.
Gaol, M. J. L., Camelia, A., & Rahmiwati, A. (2018). Analisis Faktor Risiko Kelelahan Kerja Pada Karyawan Bagian Produksi PT. Arwana Anugrah Keramik, Tbk. Jurnal Ilmu Kesehatan Masyarakat, 9: 53–63.
Nurmianto, E. (2008). Ergonomi Konsep Dasar dan Aplikasinya. Edisi Kedua. Surabaya:
Penerbit Guna Widya.
Patradhiani, R., Nopriansyah, B., & Hastarina, M. (2021). Identifikasi Postur Kerja Pengrajin Batik Jumputan Dengan Metode Job Strain Index (JSI). Journal of Industrial & Quality Engineering p-ISSN, 2303, 2715.
Prabaswari, A. D., Suryoputro, M. R., & Utomo, B. W. (2020). Analisis Postur Kerja pada Perusahaan yang Bergerak Bidang. Jurnal Penelitian Dan Aplikasi Sistem & Teknik Industri (PASTI).
Pratama, E. R., Rahayu, M., Sjafrizal. (2014). Identifikasi Tingkat Kelelahan Untuk Mengurangi Risiko Kecelakaan Kerja Di Divisi Warehouse Pt. Papandayan Cocoa Industries Dengan Pendekatan Metode Beban Kerja Mental Fatigue Level Identification to Reduce Work Accident Risk in Warehouse Division Pt. P. 2(3), 7524–7539.
Pulat, B. M. (1992). Fundamentals of Industrial Ergonomic. AT & T Network System.
Oklahoma.
Rahayu, M., & Juhara, S. (2020). Analisis Beban Kerja Fisiologis Mahasiswa Saat Praktikum
Analisa Perancangan Kerja Dengan Menggunakan Metode 10 Denyut.
Rahmawati, R., & Tarwaka, P. 2020. Hubungan Beban Kerja Fisik Dengan Kelelahan Kerja Pada Tenaga Kerja Di Bagian Percetakan Dan Pengecoran PT. Aneka Adhilogam Karya Di Desa Batur Kecamatan Ceper Kabupaten Klaten (Doctoral dissertation, Universitas Muhammadiyah Surakarta).
Salcha, M. A., Kessi, A. T. F., Juliani, A., & Ahjad, M. (2020). Tingkat Risiko Ergonomi Pada Aktivitas Manual Handling di Gudang Bulog Baru Panaikang I Kota Makassar. Jurnal Mitrasehat, 10: 100-111.
Setyawati, L. (2010). Selintas tentang Kelelahan Kerja.
Suhardi, Bambang. (2008). Perancangan Sistem Kerja dan Ergonomi Jilid 2. Jakarta:
Direktorat Pembinaan Sekolah Menengah Kejuruan.
Sulaiman, F., & Sari, Y. P. (2018). Analisis Postur Kerja Pekerja Proses Pengeasahan Batu Akik Dengan Menggunakan Metode Reba. Jurnal Optimalisasi, 16–25.
Suma’mur, (2009). Higiene Perusahaan dan Keselamatan Kerja Edisi II Cetakan. Jakarta: CV.
SagungSeto.
Susihono W. (2012). Perbaikan Postur Kerja untuk Mengurangi Keluhan Musculoskeletal dengan Pendekatan Metode OWAS. J Teknik Industri- Spektrum Industri. 10(1): 69-81.
Tarwaka. (2010). Ergonomi Industri: Dasar-dasar Pengetahuan Ergonomi dan Aplikasi di Tempat Kerja.
Tayyari, F. & Smith, J. L. (1997). Occupational ergonomics: Principles and applications, Chapman & Hall Title.
Umyati, A., Kusumaningrum, E., Susihono, W., & Gunawan, A. (2020). Pengukuran Tingkat Kelelahan Kerja Karyawan pada Departemen Operation Director PT. XYZ. Journal Industrial Servicess, 6(1), 62-65.
Wilson, J. R. (1995). Evaluation of Human Work: A Practical Ergonomics Methodology.
London: Taylor and Franchis Ltd.
Zen, Z. H., & Zamora, B. (2016). Analisis Postur Kerja Menggunakan Metode Rapid Entire Body Assessment (REBA). Photon: Jurnal Sain Dan Kesehatan, 7: 113–119.
