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Ergonomic Risk Factors, Musculoskeletal Disorder and Passenger Comfort (in the Context of Commuter Trains in Malaysia)
1*Fatimah Abdullah, 2Zainudin Awang, 3Wan Hasrulnizzam Wan Mahmood
Faculty of Mechanical Engineering and Manufacturing Technology Universiti Teknikal Malaysia Melaka (UTeM)
Malaysia
*Corresponding Author E-mail: fatimah.abd@mara.gov.my
Received:06th September 2021 Accepted: 31st October 2021 Published: 28th November 2021 ABSTRACT
The study aims to validate the research instrument for measuring the ergonomic risk factor, musculoskeletal disorders, and passenger comfort for the users who use the Commuter train as the main transportation every day to enable them to go to the desired destination.
The self-administered questionnaire was distributed to the passenger by using simple random sampling. The Confirmatory Factor Analysis (CFA) procedure was carried out to validate the instruments by assessing for unidimensionality, validity, and reliability. The study also tested the proposed hypothesis using Structural Equation Model (SEM). Furthermore, the results were confirmed through the bootstrapping procedure. The finding indicated that the measurement model of this construct achieved the requirement for construct validity and reliability. The study found Musculoskeletal Disorder fully mediates the relationship between Ergonomic Risk Factors and Passenger Comfort. Further study should be conducted on the different types of public transport trains in Malaysia due to the number of users who take this public transport is increasing day by day.
Keywords: Ergonomic risk factors, Musculoskeletal Disorder, Passenger Comfort, Structural Equation Model and Commuter OPEN ACCESS
BACKGROUND AND INTRODUCTION
Developed countries have a strong economy and have public transport services and networks that are interconnected with each other and facilitate the movement of passengers from one place to another. The public transport sector is a driver of national growth, and the provision of a quality transport system is essential to achieve the aspirations of developed countries.
In Malaysia, the transport sector has grown rapidly, exceeding 5% since 2004 and contributing 3.6% to GDP (Gross Domestic Product) in 2017 (Kementerian Pengangkutan Malaysia, 2019). To meet the objectives of the national transportation policy 2019-2030, where the government needs to provide mobility that meets the demands of the people and is inclusive, a transportation system that meets consumer satisfaction is one factor to catalyze these objectives.
There are various railway operators face the same issues and challenges when it comes to satisfy the customer’s wants and demand while maintaining high performance. The railway service providers must act and figure out the new plan towards effectiveness strategies of business that can be implemented into the service sector. Urban rail transit operations industries in Malaysia still lack an effective assessment instrument to define the scarcity factors in their product services, which is a crucial requirement for developing services, increasing riding, and introducing a sustainable transport strategy (Heng et al., 2021). Indeed, excellent quality of service and facilities comfort will improve customer satisfaction (Lestari & Murjito,
2020), which contributes to consumer retention and encouraging recommendations. There is adequate research on railway service quality in developed countries and developing countries (Niu et al., 2019). Along with enhancing the operations and efficiency of the trains to improve and promote the trains systems, ergonomic risk factor consideration to fit the task of commuting to the commuter.
This will provide a healthy and more comfortable riding experience, thus giving more reason for commuters to make use of the trains (Martinez et al., 2020). The limitations exist regarding to investigation of ergonomic risk factor that can affect to the passenger’s comfort on the train industry especially the KTM Komuter Berhad.
One of the public transport available in the country is from KTM commuter, which is a link between one state to another.
With the rate of time in the train for passengers to arrive from one destination to the destination, the comfortable environment in the train is an important factor to allow passengers to feel satisfaction with the travel services experienced by them. This study considers the ergonomic risk factors in the train experienced by passengers that affect musculoskeletal disorders to those who cause passengers to feel uncomfortable while they are in the train cabin. The investigation of the impact of ergonomic risk factors in trains that affect passenger comfort, mediating role with musculoskeletal disorder on train public transport in Malaysia was investigated in this research. Subsequently, this
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investigation means to make theoretical contribution by diminishing the gap in the literature as there is no such examination yet about to inspect the ergonomic risk factor in the connection of musculoskeletal disorders experienced affecting discomfort to passengers, by mediating role with musculoskeletal disorder experienced by passengers when boarding the train.
OBJECTIVES
1. To determine the impacts of Ergonomic Risk Factors on Musculoskeletal Disorder and Passenger Comfort among Commuter Train Passengers in Malaysia.
2. To determine the mediating role of Musculoskeletal Disorder in the relationship between Ergonomic Risk Factors and Passenger Comfort among Commuter Train Passengers in Malaysia.
LITERATURE REVIEW Ergonomic Risk Factor
Ergonomic is the science of fitting jobs to workers instead of getting the worker to fit the job. It focuses on designing workstations, tools, and work tasks for safety, efficiency, and comfort. Ergonomics seeks to decrease fatigue and injuries and increase comfort, productivity, job satisfaction, and safety because work injuries are not inevitable, and a well-designed job should not hurt the workers (OSHA.Gov, 2018).
Ergonomics can be defined as the scientific discipline that concerns understanding the interaction between humans and the work system. Meanwhile, for ergonomic risk factor is described as an attribute, characteristic or exposure that may cause or contribute to a musculoskeletal injury, the mere presence of a risk factor may not in itself result in an injury (Sanmugum et al., 2020). As described in the paragraph above is the definition of ergonomic risk factor, while for the purpose and description of musculoskeletal disorders will be described in the paragraph below under subchapter 2.2. as a result of being exposed to the ergonomic risks in this train, the passengers in the train cabin have musculoskeletal disorders.
Several studies from past researchers examine the ergonomic effects of this risk factor that impact musculoskeletal disorders.
This includes studies on workplace environments that are not ergonomic and have ergonomic risks that have side effects to this musculoskeletal disorder. among them are studies from the dental medicine industry (Plessas & Bernardes Delgado, 2018) (Ohlendorf et al., 2020), the construction industry (Anagha R, 2020) (Abinaya Ishwarya & Rajkumar, 2020). As a result of this lack of understanding and exposure to ergonomic risks, computer users have also experienced this musculoskeletal disorder among higher learning students who are exposed for too long in front of a laptop/or computer (Arshad et al., 2020). This ergonomic risk is also experienced by vulnerable those working in the office (Salehi et al., 2020).
Although it looks comfortable and there is no risk, but so without being aware of the importance of knowing that they are exposed to musculoskeletal disorders due to ergonomic risk environment when seating posture, brightness, duration time while in front of a laptop/pc because taking this ergonomic issue is taken lightly and not seriously as it is not experienced in a short period of time.
Consciously or unconsciously, this ergonomic risk factor should be taken into account and should be given exposure to all because the ergonomic factor is something we do not realize how the risk can occur, but it affects the level of health to anyone who has been exposed to this risk in one long term.
This study is about ergonomic risks that are not realized by train users that affect this musculoskeletal disorder. Train users need to take note of this issue and be given knowledge disclosure to train users about the importance of knowing and caring about ergonomic risks that can affect musculoskeletal disorders that they will experience as a result of being exposed to these risks. Everything considered, in perspective on the above explanation, it is hypothesized that,
H1: Ergonomic Risk Factors has significant effect on Musculoskeletal Disorder among Commuter Train Passenger in Malaysia.
In general, two or more risk factors may be present simultaneously, thereby increasing the risk of injury. But the term ergonomic given earlier refers to the employee's situation and the environmental conditions in the workplace. For this study, ergonomics is more focused on the knowledge of ergonomics in passengers' situations when boarding a train.
Furthermore, this study focuses more on the effect of this ergonomic risk factor on passengers when the facilities provided do not provide comfort, which leaves consumers dissatisfied with the services offered when boarding this train.
There are many studies on ergonomics related to workers and the conditions of the workplace environment, for example like automotive part manufacturer (Mahboobi et al., 2020) and office environment (Mahboobi et al., 2020). Still, few studies have been obtained on ergonomic studies risk factors involving passengers and public vehicles. For example, a study on the ergonomic design of passenger cabins consists of a survey on the cabin's design (J. Gumasing et al., 2020) and a study from Gumasing that studies ergonomic design in the LRT but only involves special needs passengers (Gumasing et al., 2019), but no details on the ergonomic risk factors experienced by such passengers.
While the use of public transport such as trains and transit is increasingly widespread in modern times today. There are studies on ergonomic risk factors involving these public vehicles when these ergonomic effects affect employees working in these public vehicles (train drivers) (Araújo et al., 2018); (lorry drivers) (Arminas & Nurwahidah, 2019).
However, no studies lead to ergonomic risk factors that affect the users of these public vehicles despite their large population who use these vehicles every day to communicate from one place to another.
As we all know, there are various studies on ergonomic risks that occur in the workplace. Among them is a study from Sanmugum which examines the risk of workers working in manufacturing offshore containers involving employee activities such as awkward posture, repetitive motion, static and sustain work postures, vibration, insufficient ventilation, exposure to noise and working in extreme temperatures (Sanmugum et al., 2020). There are various ergonomic risk factors in the environment in this public vehicle. Considering the appropriate ergonomic risk factors such as noise,
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vibration, and ventilation in this study is expected to give consumers a branch of choice that factors are more affecting them in providing a comfortable journey to passengers. Other researchers have conducted various studies on the different factors that cause consumer discomfort due to dealing with this less ergonomic environment involving public transport, as described in the paragraphs below. Everything is considered, in perspective on the above explanation, it is hypothesized that,
H3: Ergonomic Risk Factors has significant effect on Passenger Comfort among Commuter Train Passenger in Malaysia.
Noise
Railway noise is a major environmental and public health problem. When the train is moving, a few clear sounds are emitted; the noise of the train engine and the wheel turning on the rail (Čižiūnienė et al., 2020). As a result of this noise, passengers emit noise inside the train and outside (while at the station). Most of the studies on train-related noise are noise disturbances to the surrounding area of the train route faced by residents in the vicinity of the train travel route (Smith et al., 2016). Smith noted that the effects of the noise disrupted sleep for residents around the railway area. Apart from that, there is also an analysis of train exterior noise in the train station area in Medan City, Indonesia (Indrayani et al., 2021) by using a sound level meter and analyze the effect of train operating time on noise levels. The development of acoustic to achieve the listener’s comfort has significantly been developed. Development in providing less noisy train services and in turn provide comfort to passengers has been greatly developed. As informed in the paragraph above, this study adapts indoor building spaces where the noise comfort level is not only for the building environment but also in transportation, especially passenger trains (Zakri et al., 2019a). The concept of being in a train is more or less in indoor building spaces that emphasize the risk factors of illumination, acoustics, thermal comfort, vibration, noise, and ventilation (Sharma & Sharma, 2020).
Only a few studies involving noise in the train itself along its journey, as the study conducted by Zhang, have discussed abnormal interior noise occurring in a high-speed train (Zhang et al., 2018). Continuing from previous studies, Zhang has also made another study on noise around the high-speed train's exterior and interior noise source locations in China (Zhang et al., 2019). However, it still revolves around interior noise inside trains, a study from Keysha that compares noise from trains of different classes and journey times for the most famous trains in Indonesia (Zakri et al., 2019b). Interior noise of trains significantly affects vehicles ’ride comfort and therefore is one of the critical issues to be addressed in the design, manufacture, and operation of these train facilities. However, there is still no study of noise in the train during its journey that involves the comfort of passengers who use the facility. In addition, what needs to be emphasized is that noise exposure annoys, leading to physiological and psychological stress responses in some individuals; stress responses are associated with lower mood and performance. (Clark &
Paunovic, 2018).
Ventilation
In keeping with the current modern development of rail, which consumers increasingly use as the pulse of their transportation for movement, the train is an indispensable component of large cities. For a realistic chance to shift the passengers to trains, the attractiveness of this transport mode has to be increased (Lange et al., 2019). Ventilation is the principal measure for optimizing the complex physical environment inside the train cabin. Environmental health has become increasingly important and attracted attention from numerous researchers in decent decades (Chen et al., 2020) (Liu & Lee, 2020). The main objective of the ventilation of passenger compartments is to improve passenger comfort by adjusting the interior temperature, humidity, and air quality (Y. Tao et al., 2019) (Schmeling & Bosbach, 2017). However, the lack of research on the ventilation factor in trains may lead to the neglect of the environmental health effects. With the increase in the number of passengers in the train cabin, giving an unhealthy ventilation system to the train passengers.
The study involving ventilation closely related to the railway was from Yueming, but it involved measuring ventilation conditions inside the subway station (Wen et al., 2020). The ventilation inside the train cabin has been investigated with some other researchers too. (Talaee et al., 2019) made a study on induced airflow of ventilation inside metro train cabin in accelerating and decelerating modes. Apart from that, this study on ventilation is not only done in the train, but it also involves air conditioning filters, interior ventilation systems, tunnel environments and air quality platform which has been done by Yingying (Cha et al., 2018) who studied the ventilation situation for train services in Sweden. P Lange has also studied the ventilation system with regard to passenger comfort in train cabin by taking into account the factors of air temperature, air velocity, mean radiant temperature, relative humidity, metabolic rate, and clothing insulation by taking into account the level of passenger density in the train (Lange et al., 2019). But the same situation with other ergonomic risk factors, this ventilation study that has been studied does not correlate the level of passenger comfort to the ventilation factor in the train. It takes into account the evaluation rate given by users after they use this public vehicle.
Vibration
As is well known, most studies on noise and vibration are often closely related to each other. This is because strong vibrations contribute to the production of sound. For example, in the situation of a moving train, the higher the speed of the train, the exterior noise and vibrations that will be generated will be stronger like a fast train (Tetsuya et al., 2017). As defined in Oxford Dictionaries, Vibration is “an instance of vibrating or a person’s emotional state, the atmosphere of a place, the associations of an object, as communicated to and felt by others.” In physic, vibration is defined as an “oscillation of the parts of a fluid or an elastic solid whose equilibrium has been disturbed or of an electromagnetic wave”. In ergonomic meaning, vibration is defined as any regular movement a body makes about a fixed point (Kolgiri et al., 2016).
Some studies state that the generation of vibration from train movement affects the damage to the tunnel of the train route (Zhao et al., 2019) (Nezhadshahmohammad et al., 2021). The
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increase of urbanization and the development of urban rail transit are interdependent. However, along with the increased urbanization and growth of rail infrastructure, the distance between urban and railway corridors decreases, resulting in growing concerns about railway-induced vibration. Studies involving the effects of vibration on buildings around train tracks are studied (Z. Tao et al., 2019). All studies related to train vibration involve railways, tunnels (Avci et al., 2020), buildings along the train route (Smirnov et al., 2020), and vibration located in the rail station area. Accordingly, there is a study by Milan (Saliya et al., 2020) that uses intelligent systems that can monitor parameters that include temperature, humidity, motion detection, and ambient vibration that take into account the parameter readings in the train while the train is moving from one place to place. (Cai et al., 2020) have made a study to find the source of abnormal vibration coming from a moving train through the vibration analysis method. (Fatimah, 2019) has made a study on vibration readings obtained when the train is moving by using a tri-axial pad to obtain information on the value of vibration in some floor areas of passengers standing or sitting (at seat area, at door are, at the gangway) in which area has the highest vibrate value when the train is moving. However, there is still a lack of research on the state of vibration in the train itself experienced by train passengers as their experience boarding the train.
Musculoskeletal Disorder (MSDs)
Many studies of ergonomic risk factors are closely related to this Musculoskeletal Disorder (Qureshi et al., 2019) (Dinar et al., 2018). Musculoskeletal Disorders (MSDs) are injuries and disorders of the soft tissues like muscle, tendons, ligaments, joints, and cartilage (Bhattacharya et al., 2001). MSDs are characterized by severe pain, acute musculoskeletal spasms occurring due to awkward occupational work postures, and repetitive physical movements. The body has limits and can fail or wear out when abused or misused. MSDs are defined as injuries to muscle, tendons, ligaments, joints, nerves, and discs caused or aggravated by repetitive action or an environment that does not follow safe and healthy work practices (OSHA.Gov, 2018). Thus, MSDs are categorized as occupational health hazards and may hamper workplace productivity (Qureshi et al., 2019).
As informed in the above writing earlier, most ergonomic risk factors and their negative effects on getting MSDs to respect the work area environment (Dinar et al., 2018)(Hossain et al., 2018). Apart from the workplace environment that affects MSDs, the handling of non-ergonomic tools in performing daily tasks also affects MSDs to such workers (Li et al., 2019). For example, suffered happen to the workers after operating the vehicles in non -ergonomic environmental conditions over a period of time (Laal et al., 2018). Every day some 8 million commuters use the city’s suburban rail system, traveling on more than 2800 trains a day. As a result, the network is severely overcrowded during peak hours when the number of passengers exceeds the network carrying capacity by more than four times (Patil et al., 2018).
Yet there are studies on MSDs associated with train users are among train workers who operate these vehicles either as train drivers (Murko & Meško, 2019) or workers who make train
maintenance (Khan & Singh, 2018) (Landsbergis et al., 2019)(Thakur et al., 2019). Because workers in this train maintenance division are exposed to biomechanical, vibration, and work organization exposure among active, retired. Out of disability for these workers, it is suspected to be risk factors for various work-related MSDs. However, few studies on the effects of this musculoskeletal disorder faced by train passengers as a result of the risks experienced as a result of the non -ergonomic environment experienced by the train passengers. For example, Vrushali (Patil et al., 2018) describes the incidence of musculoskeletal disorders in commuters among train passengers using train services in Mumbai suburban railway daily.
The study on passenger activity in trains that affects passenger posture and discomfort was also given attention by Sumalee, who made a study based on train users in Thailand train services (Udomboonyanupap et al., 2021). Passenger activities such as sleeping, reading, talking or discussing, using smartphones differed in duration, and others affect the passenger's musculoskeletal disorder due to exposure to a non-ergonomic environment during the fell experience while boarding the train.
Passenger Comfort
With the rapid economic growth and development of public transport system services becoming more widespread, people are more willing to travel by train. Thus, there is an increasing requirement for passenger comfort of train travel for Malaysian users, especially in Kuala Lumpur. A comfortable train transportation system is determined by a combination of physical and psychological factors. A comfortable environment inside a train cabin can be regarded as a resource for social consumption, and comfortable passengers benefit from the generalized cost paid by passengers to board the public transport. Furthermore, from the point of view of train users themselves, they use the train as their daily transportation to connect from one place to another because they can take a rest and handle their own business in a comfortable passenger cabin coach. Additionally, during and after the journey, passengers will spend less time getting rid of travel fatigue. Accordingly, providing a comfortable train transportation service is the most important measure to attract passengers (Huang & Shuai, 2018).
Many studies have been studied before on the level of passenger comfort on train services. Among them from Wencheng, who compared passenger comfort levels for two types of trains in Shanghai, China (Huang & Shuai, 2018). In addition to studying passenger comfort level inside the train cabin, Yanran studied passenger comfort level using Sperling Method for passenger trains in Australia (Jiang et al., 2019).
However, it is difficult to establish a universal set of requirements because passengers' perception of comfort may be affected by various factors such as vibration, noise, track condition, ventilation inside the train. In some other research, the railway's riding comfort is determined by vibration, noise, temperature, humidity, and many other factors (Suzuki, 1998).
If viewed from an ergonomic point of view, all the elements studied, the factors that affect passenger comfort, are present in ergonomic risk, as discussed earlier in the paragraph above.
This comfort is the feeling of an individual feeling safe and
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satisfied with the services provided. The comfort gained by passengers when boarding this train is when the user will repeat using this train service, giving to the loyalty factor and becoming a loyal user of this public vehicle (Losada-Rojas et al., 2019).
As discussed in the paragraph above, where the passenger activity also affects the MSDs, the same goes for the level of comfort of the passengers when boarding this train. Through a study from Sajia, where this study identifies the activity performed by the train passenger and corresponding posture of the passengers, duration of the activities and assess the comfort in respect of the performed activity and postures in other words, this study makes ergonomic analysis of Bangladeshi train passengers (Shifa & Kibria, 2018).). More specific research like the seat measurement method that emphasizes the interactions between the human body and seats has also been developed to study the passengers
’comfort level (Wu & Qiu, 2020). However, riding comfort is a subjective feeling of passengers, and there are too many influence factors that cannot be well measured (Munawir et al., 2017). For example, many studies have related to the comfort level of passengers when boarding the train, among them is the effect of the comfort level on the train when the train passes through the vehicle-track interaction (Sadeghi et al., 2019).
Apart from that, the level of discomfort of passengers when in a crowded train cabin condition (Bansal et al., 2019) where overcrowding situation is an externally that provokes on passenger mentality due to have to stand up along the journey and have discomfort experienced the feeling when traveling using the train. In addition to the study on comfort when riding a train coupled with a survey from Tao that studied the effect of long-wavelength track irregularities on railway routes that influence ride comfort among the train users (Xin et al., 2019).
Environmental quality in public rail transit is also one of the catalysts to the factors that contribute to passenger comfort (Mao et al., 2019). All the examples of studies mentioned on the comfort of riding this train may affect passengers' feelings, and there is no universal standard measurement method for riding comfort until now.
In this study, we concentrate on the ergonomic risk factors (vibration, noise, and ventilation) that affect musculoskeletal disorders to passengers, involving the comfort level of passengers when boarding a train from one destination to another. Everything considered, in light of the above explanation, it is theorized that,
H2: Musculoskeletal Disorder has significant effect on Passenger Comfort among Commuter Train Passenger in Malaysia.
What’s more, the more profound thought for exploration shape uncovers that the previously referenced variable has convoluted associations with one another, which are intervened by implication during a third variable. Additionally, by alluded back to the writing survey, some researchers inspected musculoskeletal disorder as a mediator (Gumasing et al., 2019). Studies on ergonomic risk factors that affect musculoskeletal disorders as well as cause discomfort to
commuter motorbike users have also been reviewed by (Tony et al., 2020). Henceforth, it could be hypothesized that, H4: Musculoskeletal Disorder mediates the relationship between Ergonomic Risk Factors and Passenger Comfort among Commuter Train Passenger in Malaysia.
Thus, the connections among the constructs in the form can be attracted to a comprehensive conceptual model, for example the underneath outline in Figure 1 and Figure 2 as shown below:
Figure 1. The Framework of the study
Figure 2. The Framework of the study showing the constructs, components, and items
Source: The Framework of study developed by the researchers based on literature review
The hypothesis of interest, as shown in Figure 1 listed in Table 1.
Table 1: The Hypothesis Statement of the Study
Hypothesis statement Statistical Analysis to
employ H1 Ergonomic Factors has significant effect
on M-Skeletal Disorder among Commuter Train Passenger in Malaysia.
Path Analysis in SEM H2 M-Skeletal Disorder has significant effect
on Passenger Comfort among Commuter Train Passenger in Malaysia.
Path Analysis in SEM
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H3 Ergonomic Factors has significant effect on Passenger Comfort among Commuter Train Passenger in Malaysia.
Path Analysis in SEM H4 M-Skeletal Disorder mediates the
relationship between Ergonomic Factors and Passenger Comfort among Commuter Train Passenger in Malaysia.
Path Analysis in SEM and Bootstrapping
METHODS
Methods of Sampling and Data Collection
The target population of this study was KTM Commuter train passengers of public transport companies in Malaysia. Thus, the sampling frame consists of customers using this public transport service to arrive at their destination, which consists of various destinations. This study employed a quantitative approach in estimating the inter-relationship among the constructs, as presented in Figure 1 and Figure 2. Precisely, the method used was Structural Equation Modelling (SEM) in IBM-SPSS-Amos 25.0. The present research was carried out at two well-known train stations: Pulau Sebang and KL Sentral stations. They were chosen due to their strategic location.
Pulau Sebang is the only KTM Komuter at Melaka, which is the train travel link from Melaka to Kuala Lumpur. The location of KL Sentral was chosen because KL Sentral is a communication center where it involves various types of public transport concentrated there for passengers to go everywhere they want to go. These two stations were also chosen because of the flexibility in approaching the respondents for their objective and subjective views and comments on the performance of commuter service in both stations. The journey from Pulau Sebang to KL Sentral also takes a long time, which is two hours, which is why these two stations were chosen to allow passengers to complete the questionnaire questions given. A set of questionnaires was distributed to selected KTM Komuter passengers who were waiting for their respective train at both selected stations. Questions are also given to train passengers who are in the train who are willing to answer the survey questions on their way to their destination. An interview was also conducted with some of the users of the commuter. However, this was fully depended on their willingness to give feedback on those highlighted issues.
These responses were collected by traveling on the same train together with the respondents. Thus, allow the respondents to have time to engage in communication while in transit.
Measurement of Construct
The ergonomic Risk Factor construct was measured using items adapted from the previous study regarding ergonomic risk factors that other researchers have previously studied that can be used and adapted to be one of the questionnaire questions for this study. This ergonomic risk factor construct contains three sub-constructs, namely noise, vibration, and ventilation. Each sub-construct contains 10 question items regarding ergonomic risks experienced by users while riding this train. Using EFA, three items from the noise construct have been removed, while two items will be removed for the vibration construct. For construct musculoskeletal disorder, 11 items need to be evaluated by users about which body part is experienced by users who feel pain by them. As a result of previous studies on passenger comfort, there are 8 items have been identified for use in this study.
Pretest and Pilot Testing of the Instrument
Since the instruments were adapted from any source of previous research that related to this study, the questionnaire had been modified to suit the current study, the researcher sent the modified instruments to the respective experts for content validity, face validity and criterion validity assessment (Bahkia et al., 2019; Rahlin et al., 2019a; Shkeer & Awang, 2019a; Teike Lüthi et al., 2020). Once the instruments were receive back, the researcher has modified the instruments accordingly based on comments made by the respective experts. Once completed, the researcher conducted the pilot study where some 110 self-administered questionnaires were sent to selected respondents for data collection. Using the data from pilot study, the researcher conducted the Exploratory Factor Analysis (EFA) procedure to explore the usefulness of the items measuring their receptive construct.
The EFA was carried out using IBM-SPSS 25.0. Based on the EFA results, certain items were removed due to poor factor loading, and the retained items were rearranged for the field study questionnaire.
Demographic Profile
Respondents were asked to provide their demographic information such as age, educational level, job title, year of experience using commuters, and time travel using KTM Commuter.
DATA COLLECTION
The study selected a random sample of 400 respondents from the sampling frame using Simple Random Sampling. This probability sampling method ensures the randomness of the selection and representativeness of the sample towards the target population. Thus, the procedure met the requirement for parametric statistical analysis. The selected respondents were given a self-administered questionnaire to attend at their own convenient time without fear or pressure. Once completed, they submit the questionnaire to the researcher on the site (at the station or inside the train). The researcher received back a total of 361 completed and usable response. The return rate was 90.25%.
RESULTS AND DISCUSSION The Confirmatory Factor Analysis
Using the field study data, the Confirmatory Factor Analysis (CFA) was carried out to validate the measurement model of latent construct. The CFA procedure assessed three types of validity, namely construct validity, convergent validity, and discriminant validity together with composite reliability (Rahlin et al., 2019b; Johani et al., 2021), Once the CFA procedure was completed, the study developed the structural model and performed the Structural Equation Model (SEM) procedure to estimate the inter-relationships among the constructs in the model (Aimran et al., 2017a), (Aimran et al., 2017b). Using the results from SEM, the study tested the proposed hypothesis of this study. Both CFA and SEM were carried out by using IBM- SPSS-AMOS 25.0. The significance of this indirect effect was using bootstrapping procedures to confirm the significance of the mediation effect. Both direct and indirect effects were computed using 1000 bootstrapped samples. 90% confidence interval was computed by determining the p-value of significance two tails of the indirect effect in bootstrapping
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procedure. The p-value is 0.01, thus, the indirect effect was statistically significant.
Figure 3. The Confirmatory Factor Analysis (CFA) results The Confirmatory Factor Analysis output are presented in Figure 3. According to Awang et al. (2018), construct validity is assessed through the fitness indexes. There are three fit categories to fulfil namely, Absolute Fit, Incremental Fit, and Parsimonious Fit. The CFA results produced the following fitness indexes as shown in Table 2. The Fitness Indexes, which indicates Construct Validity is RMSEA=0.055, CFI=0.952, and Chisq/df=2.093. The measurement for this model has achieved the requirement for Construct Validity, thus we can conclude that this model have a valid construct.
Table 2. The Assessment for Construct Validity Name of
Category Name of Index Level of Acceptance Index
Value Comment
Absolute Fit RMSEA <0.08 0.055 Fitness level achieved Incremental Fit CFI >0.9 0.952 Fitness level achieved Parsimonious Fit Chisq <3.0 2.093 Fitness level achieved The measurement for this model has achieved the requirement for Construct Validity
Figure 4. The Standard Regression Path Coefficient between Construct (SEM output)
The convergent validity and composite reliability are computed using factor loading for every item retained in the model after the CFA procedure. Table 3 presented and summarize the component, the items under every component, the factor loading for every item and the computed values for Composite
Reliability (CR) and Average Variance Mode (AVE) that shown in Figure 4. The values demonstrates the factor loading for all items is above 0.60, which showed the unidimensionality of the measures (Asnawi et al., 2019). The result showed that the indicate of the convergent validity and composite reliability for this model has been achieved when all values for CR are greater than 0.6 and all values for AVE are greater than 0.5 (Bahtiar et al., 2020). Thus, this study can conclude that the composite reliability and convergent for this model construct have been achieved.
Table 3. The Composite Reliability, Convergent Validity and Discriminant Validity
Construct Item Factor Loading CR
(min 0.6) AVE
(min 0.5) √AVE Convergent Validity Ergonomic Risk
Factor Noise 0.84 0.892 0.734 0.857 Yes Ventilation 0.87
Vibration 0.86 Musculoskeletal
Disorder MS1 0.73 0.908 0.500 0.707 Yes
MS2 0.75
MS3 0.65
MS4 0.70
MS5 0.74
MS6 0.69
MS7 0.63
MS8 0.66
MS9 0.69
MS10 0.66 MS11 0.65 Passenger
Comfort CM1 0.78 0.923 0.601 0.775 Yes
CM2 0.77
CM3 0.79
CM4 0.74
CM5 0.74
CM6 0.76
CM7 0.81
CM8 0.81
The following stage is to evaluate the discriminant validity of the latent constructs, which was made through the discriminant validity index summary, as shown in Table 3.
Discriminant validity is to check whether the construct in this model research is achieved if the coefficient of correlation among the components does not exceed 0.85 (Noor et al., 2015). Since all diagonal values are higher than any other values in its rows and columns, the discriminant validity of all constructs are accomplished (Shkeer & Awang, 2019b).
Concerning the composite reliability, the value of CR for all constructs are higher than 0.6, which implied the measurement model for all constructs had accomplished the composite reliability requirement (Mahfouz et al., 2019).
Table 4. Discriminant Validity Indexes Summary of all construct, Construct Reliability and Average Variance Extracted
Average Variance Extracted (AVE)
Construct Reliability (CR)
Ergonomic
Risk Factor Musculoskeletal Disorder Passenger
Comfort
Ergonomic
Risk Factor 0.892 0.734 0.857 Musculoskele
tal Disorder 0.908 0.500 0.65 0.707 Passenger
Comfort 0.923 0.601 0.57 0.72 0.775
This study also needs to assess the distribution of items measuring the research model construct. The study is to
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obtain the assessment of normality distribution from the text- output of IBM-SPSS-AMOS and presented in Table 4. For the procedure using Maximum Likelihood Estimator (MLE), the normality assessment is made using skewness values for all items should fall range between -1.5 and 1.5 for the data to be acceptable (because the sample size is more than 200) and to be normal distributed, or at least the data distribution does not depart from normality distribution. The normality distribution of the dataset is assessed using the value of skewness and kurtosis for every item. The outcome demonstrated the skewness for all items in the range between -0.809 and 0.53, while the estimation of kurtosis fall in the range between 0.183 and 1.309. These two measures indicated the data does not depart from normality distribution and hence, meet the assumption for employing parametric statistical analysis.
Table 5. The assessment of normality of the items Variable Min Max Skew c.r. kurtosis c.r.
MS11 2.000 5.000 -0.159 -1.234 0.183 -0.711 MS10 2.000 5.000 -0.124 -0.963 0.256 -0.993 MS9 2.000 5.000 -0.076 -0.586 0.420 -1.628 MS8 1.000 5.000 -0.131 -1.012 0.220 -0.852 MS7 1.000 5.000 -0.483 -3.744 0.690 2.676 MS6 2.000 5.000 -.115 -0.889 0.158 -0.611 MS5 2.000 5.000 -.184 -1.424 0.009 0.035 MS4 2.000 5.000 -.009 -0.071 0.239 -0.928
MS3 2.000 5.000 .053 0.412 0.284 -1.103
MS2 2.000 5.000 -.265 -2.057 0.099 -0.385 MS1 2.000 5.000 -.035 -0.272 0.285 -1.106 CM8 2.000 5.000 -.353 -2.737 0.201 0.779 CM7 2.000 5.000 -.390 -3.022 0.052 -0.202 CM6 2.000 5.000 -.154 -1.196 0.189 -0.731 CM5 2.000 5.000 -.160 -1.242 0.054 -0.209 CM4 2.000 5.000 -.069 -0.532 0.422 -1.637 CM3 2.000 5.000 -.143 -1.113 0.288 -1.115 CM2 2.000 5.000 -.080 -0.622 0.252 -0.977 CM1 2.000 5.000 -.375 -2.907 0.280 1.085 Noise 1.000 5.000 -.759 -5.886 1.261 4.892 Ventilation 1.000 5.000 -.616 -4.774 1.022 3.964 Vibration 1.000 5.000 -.809 -6.276 1.309 5.076
Multivariate 58.659 17.149
STRUCTURAL EQUATION MODELLING (SEM)
Figure 6. The Regression Path Coefficient between Construct (SEM output)
The hypothesis testing results in Table 6 revealed the significance of four hypothesis. By referring to Figure 3, the unstandardized estimation graphic from SPSS-AMOS 24.0, which gives the standard regression path coefficient between constructs. A description of the results of the hypothesis
findings of this study is as follows. H1, which conveyed a positive relationship between ergonomic risk factors in the train and musculoskeletal disorders experienced by passengers, has been supported (H1: ᵝ = 0.49, CR = 10.71, p
= 0.001). H2 conveyed that musculoskeletal disorders experienced by users when boarding a train have a positive effect on passenger comfort and have also been supported by the results (H2: ᵝ = -0.75, CR = -5.54, p = 0.001). Finally, H3 conveyed a positive relationship between ergonomic risk factors in the train affecting the comfort level of passengers who boarded the train was not empirically supported (H3: ᵝ = -0.19, CR = -1.94, p = 0.052). The content yield came about because executing the structural equation model (SEM) strategy is appeared in Table 7 by referring Figure 4. Right off the bat, the indirect impact of the ergonomic risk factor on musculoskeletal disorder was observed to be positive and significant. In this way, H1 is supported. Besides, the indirect impact of the musculoskeletal disorder on passenger comfort was observed to be negative and significant. Along these lines, H2 is also supported. Further, the direct impact of the ergonomic risk factor on passenger comfort was more than 0.05 and not significant. In this way, H3 is not supported.
Table 7. The Regression Path Coefficient and Its Significance
Construct Path Construct Estimate S.E. C.R. P Decision Hypothesis Musculoskeletal
Disorder <--- Ergonomic Risk
Factors 0.491 0.046 10.714 0.001 Positive and Significant Supported Passenger
Comfort
<--- Musculoskeletal
Disorder -0.747 0.135 -5.537 0.001 Negative and Significant
Supported Passenger
Comfort <--- Ergonomic Risk
Factors -0.190 0.098 -1.944 0.052 Negative and Not significant Not Supported
Test of Mediation
Figure 5. The procedure for testing mediator in the model The bootstrapping procedure is to reconfirm the hypothesis testing in Figure 5 is presented in Table 8. The study employed the Maximum Likelihood bootstrapping procedure using 5000 bootstrap samples with both percentile confidence intervals and biased-corrected confidence interval are set at 0.95.
Bootstrapping results in Table 8 shows that Ergonomic Risk Factor has a significant indirect effect on Passenger Comfort (Beta=-0.652, p=0.002), and Ergonomic Risk Factor has significant direct effect on Passenger Comfort with involving Musculoskeletal Disorder as the mediator in the relationship (Beta=0.138, p=0.051). Based on bootstrapping result in Table 8, researchers conclude that bootstrapping is consistent with result in Figure 5. These results supported hypothesis 4, which indicated that Musculoskeletal Disorder fully mediated the relationship between Ergonomic Risk Factor and Passenger Comfort.
1. The indirect effect a = 0.65 (statistically significant) 2. The indirect effect b = -0.61 (statistically significant) 3. The direct effect c = 0.18 (not statistically significant) 4. Thus, the mediation occur since both a and b are
significant
5. The type of mediation is full mediation since the direct effect c is not statistically significant
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Table 8. The Bootstrapping Procedure to confirm the mediation Test in Figure 6
Indirect Effect (a x
b) Direct Effect (c)
Bootstrapping Value -0.652 -0.138
Probability Value 0.002 0.051
Result on Mediation Significant Not Significant Type of Mediation Full Mediation since the direct effect is not
significant
The result revealed that ergonomic risk factor is an important contributing factor to the comfort of KTM Commuter passengers. Additionally, results indicated that musculoskeletal disorder is the most prominent factor affecting passenger comfort. Thus, these results bring comprehensive understandings into the mechanisms by which climate factors like ergonomic risk factors contribute to musculoskeletal disorder and, consequently, the effect of musculoskeletal disorder's effect on the comfort of passengers boarding this train.
DISCUSSION
The first hypothesis recommends that the ergonomic risk factor significant effect on the musculoskeletal disorder among KTM Commuter train passengers in Malaysia. The after- effects of this examination supported this hypothesis that the ergonomic risk factor has a significant and indirect effect on the musculoskeletal disorder among KTM Commuter train passengers. All the more explicitly, Malaysian users of this public transport company for this train service who have experience riding this train and have ideal which factor is the cause of ergonomic risk when riding the train, in general, display higher risk to get musculoskeletal disorder among the passenger when riding this train. This output was additionally upheld by past examinations in various settings, which proposed were among the three factors studied (noise, vibration, and ventilation), which factor can be one of the variables contributing to the symptoms of musculoskeletal disorders to the train passengers. From the result, the ventilation got the highest vote from the passenger. This research proves that the ergonomic risks posed by ventilation are most felt by the user while on the train.
Such as the study conducted by Neil found that the effects of a non -ergonomic environment in the surrounding area led to musculoskeletal disease among the respondents for the case study (Mansfield et al., 2020). A more relevant study in train cabin environment has been made by Noor where this study has proven that negative ergonomic environment risks impact musculoskeletal disorders to train drivers (Mad Isa et al., 2018). For example, a workplace environment with high ergonomic risk, as found in a study by Edda proved that maintenance workers of machinery and equipment exposed to this ergonomic risk get the effects of this musculoskeletal disorder as a result of this risk (Capodaglio, 2020).
The second hypothesis thinks that musculoskeletal disorder has a significant effect on the passenger's comfort among KTM Commuter train passenger in Malaysia. This result was likewise supported by past examinations in various settings, which hypothesized that musculoskeletal disorder could be one element that can affect passenger comfort when riding a train along with their destination. The result shows that the
musculoskeletal disorder has a negative with significant and indirect effect to the passenger comfort. All the more explicitly, Malaysian users of this public transport company for this train service who have experience riding this train and have a higher musculoskeletal disorder would, in general, display the higher effect of passenger comfort. Aside from demonstrating the connection between musculoskeletal disorder and passenger comfort, the musculoskeletal disorder was consolidated in this examination since it may be utilized as an apparatus to gauge the best maximum service of this transportation business to the passenger. This study proves that the more passengers feel they get musculoskeletal disorder while boarding this train, the more they feel discomfort while on the train.
There are several similar studies from other researchers that substantiate the findings of this study. Sumalee, who made a study on the comfort of passengers inside the train cabin, proved that musculoskeletal disorders experienced by passengers while in the train cause discomfort to them when using these facilities (Udomboonyanupap et al., 2021).
However, the study of musculoskeletal disorders does not only focus on passengers in the train only. There are several studies on employees exposed to this disease while working, which in turn creates discomfort in doing their day job. A study by Jingjing supports this statement where workers among Chinese flight baggage handlers who suffer from this musculoskeletal disorder feel uncomfortable while doing their jobs (Wang et al., 2019). This situation creates a back pain effect among the employees.
In this examination, the effect from musculoskeletal disorders experienced by train users was estimated by evaluation measurements with numerous things. Therefore, this method is progressively steady when assessing passenger comfort. In this way, musculoskeletal disorders play an important role in the evaluation of passenger comfort due to passengers who use this train service are hardcore users who always use this train as their daily transportation; in this way, this examination discovered musculoskeletal disorder assumed as a major contributing factor in improving the comfort level of users of this train. Therefore, among these lines, the outcomes found that the user for this commuter line is prone to musculoskeletal disorders that affect the comfort level of users of this train.
The third hypothesis proposed that ergonomic risk factor has a significant effect on passenger comfort among KTM Komuter train passenger in Malaysia. However, the results in this study do not support the hypothesis. The result showed that ergonomic risk factors are negative, not significant and direct effect to the passenger comfort when riding a public transport train in Malaysia. As for terms of passengers, the train is the one important vehicle for their daily use as the users in this context recommended their opinion and evaluation against the ergonomic risks they face that affect the level of user satisfaction when boarding this train. Through the passenger questionnaires rating on the comfort of this train, the higher the ergonomic risk factor when passengers are in the train, the more passengers feel uncomfortable throughout their journey.
This statement is supported by a study from Patricia, who stated that a good ergonomic approach would provide a comfortable service to the users of this train (Filipa Pinheiro da
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Silva & Mendes, 2020). Like the study above, there are studies on ergonomic risk factors in the workplace that affect employee comfort. Among them is a study from Subir that supports the findings of this study where his study is on the electric loco pilot for Indian Railway who experience discomfort when exposed to this ergonomic risk environment (Danda et al., 2020).
The last hypothesis considers musculoskeletal disorder mediates the relationship between ergonomic risk factors and passenger comfort among KTM Komuter train passenger in Malaysia. This examination found that musculoskeletal disorders experienced by train passengers fully mediated the relationship between ergonomic risk factors that happen inside train cabins and the feeling of comfort experienced by train passengers. Some studies examine the prevention of musculoskeletal disorders from workers experienced by those exposed to the risks of this ergonomic environment to enable them to be comfortable. This study by Jordan proves that using prevention of work related to the mining work industry can reduce the musculoskeletal experienced by workers, in turn, provide a comfortable working environment to workers (Rodríguez-Ruíz et al., 2020).
In referring by this research, specifically, this study considers the experience experienced by KTM Komuter train users when using this public vehicle as their daily transportation. All the more significantly, the discoveries in this examination found that musculoskeletal disorder went about as a fully mediator between ergonomic risk factors and passenger comfort. Thus, this study showed that ergonomic risk factors affect indirectly effect and significant through musculoskeletal disorders experienced by train passenger, while direct effect and not significant to the passenger comfort. Meanwhile the musculoskeletal disorder have indirect effect and significant to the passenger comfort for the KTM Komuter user.
CONCLUSION
The present examination researched the connection between ergonomic risk factors and passenger comfort among the users in the public transport company in Malaysia. Results bolstered the hypothesized relationship between ergonomic risk factors and passenger comfort when riding train KTM Komuter. What's more, in this investigation, the researchers investigate the mediating impact of the musculoskeletal disorder on the effect of an ergonomic risk factor on passenger comfort. The research distinguished that musculoskeletal disorder is significantly mediated the relationship between ergonomic risk factors and the comfort of passengers from the user of public transportation companies' points of view. The outcomes have a few intriguing theoretical and practical ramifications. The first point, an ergonomic risk factor that includes noise, vibration, and ventilation, can build up another obligation that would emphatically influence the musculoskeletal disorder of the train passenger. The musculoskeletal disorder has been recognized as one of the factors that lead to the discomfort of train passengers. The second point, the outcome, has added to the discoveries in writing concerning the mediating role of musculoskeletal disorder that affects the passenger. The third point, the ergonomic risk factor, should be connected to the train user's passenger comfort and musculoskeletal disorder. Suppose
the company of this public transport contributes to the high environmental ergonomic risk factor in the train to passengers.
In that case, it will contribute to the increase in musculoskeletal disorders among passengers of this train. The fourth point, this model, was created to demonstrate the relationship between ergonomic risk factors, musculoskeletal disorder, and passenger comfort among the user of the train public transport in Malaysia.
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