Occupational discomfort and injuries among automotive technicians in Jeddah,Saudi Arabia: A cross-sectional study

Abstract

BACKGROUND:

Work-related musculoskeletal disorders (WMSDs) are one of the major causes of disability and early retirement. Consequently, WMSDs cost businesses billions of dollars annually due to compensation claims and productivity loss. Automotive technicians are vulnerable to WMSDs due to the nature of their work, which exposes them to numerous WMSDs risk factors.

OBJECTIVE:

This cross-sectional study aimed to evaluate the WMSD cases among technicians and evaluate their postures while working in small automotive repair shops in Jeddah, Saudi Arabia (SA).

METHODS:

The study employed a cross-sectional design. A self-administrated questionnaire and body parts discomfort survey were filled by thirty automotive technicians. A postural analysis technique was performed to assess the body postures that technicians adopt while performing the tasks, in order to estimate the associated risk of WMSD discomfort.

RESULTS:

Most automotive technicians suffer severe pain in the lower back, shoulders, neck, hands or wrists, and knees. The technicians related the pain to awkward body postures, heavy lifting, and sustained forceful movements.

CONCLUSION:

Automotive technicians are advised to level the height of the work surface as feasible, to work as close as possible to said work surface, and to avoid working with awkward body postures as much as possible.

Keywords

Musculoskeletal disorders body postures heavy lifting ergonomics assessment

1 Introduction

Industrial activities have been associated with work-related musculoskeletal disorders (WMSDs) for decades. Musculoskeletal disorders are injuries that impact the human musculoskeletal system. This impact could be on the joints, bones, muscles, tendons, ligaments, among others.

WMSDs could result in a large number of workers’ compensation days. It was estimated that WMSDs resulted in an average loss of productive time of 5.5 (standard deviation (SD) = 0.22) hours per week, which cost more than $60 billion annually [1].

Additionally, individuals who develop WMSD discomfort are prone to have a permanent disability and/or early retirement. Upper and lower body pain due to prolonged exposure to mechanical work showed a hazard ratio of 4.95 (95% CI 2.36–8.94) for permanent work disability [2]. According to the annual report from the General Organization for Social Insurance [3], 6,467 workers in Saudi Arabia had an early retirement due to permanent disability in 2018. These injuries were associated with a total compensation cost of about $40 million in 2018 alone.

A review by Hagberg, Silverstein [4] showed that body postures and load weight are significant risk factors for WMSDs. Automotive technicians often perform heavy lifting and work in awkward body postures. Previous studies showed that heavy lifting and awkward body postures are common factors to result in WMSDs in various body parts, including the low back, neck, shoulders, knees, and wrists, among automotive technicians.

A cross-sectional study by Torp et al. [5] showed that technicians’ working postures might contribute to the development of back and shoulder symptoms. They additionally demonstrated that 96% of the surveyed automotive technicians reported WMSD symptoms. The most common symptoms included low back pain (76%), neck pain (62%), head pain (55%), and shoulders pain (52%). Other cross-sectional studies [6, 7] demonstrated that low back pain among automotive technicians in Nigeria could be related to lifting heavy items and adopting awkward body postures while working. Also, it was shown that squatting for a long period was associated with low back pain among automotive technicians [8].

Another study examined the prevalence of WMSDs among Malaysia’s automotive technicians [9]. The authors demonstrated that the technicians’ highest pain and discomfort complaints were for shoulder (69.1%), legs (67.5%), and neck and lower back (66.5%). Furthermore, Nasaruddin’s colleagues described that lifting heavy objects contributed to the pain and discomfort on different body parts such as neck, back, shoulder, elbows, wrists, lower legs, and knees. Awkward body postures were also linked to the development of WMSD symptoms [9]; however, the authors did not specify which body parts were affected by poor postures.

Another cross-sectional study examined the prevalence of back pain among the 684 automotive technicians in Eastern Nigeria [10]. Abaraogu’s team showed that most participants (76.02%) were experiencing low back pain. Among those affected mechanics, 50.3% reported that the low back pain limited their work activity. Furthermore, the authors demonstrated that the prevalence of low back pain among the automotive technicians would increase with several factors, including being of older age, working five hours or more, kneeling frequently, and sustained postures, as well as lack of knowledge of ergonomic postures.

A recent cross-sectional study included 150 technicians who worked in different automotive repair shops in Malaysia to explore the risk factors associated with WMSDs and the prevalence of WMSD cases among those technicians [11]. The results demonstrated that there was a significant (p < 0.05) relationship between the psychosocial (i.e., job demand and satisfaction) and physical (i.e., loads and body postures) factors, in addition to the high temperature of the workplace, and the development of WMSDs. Furthermore, the results indicated that more than eighty percent of the surveyed technicians performed their job in awkward postures such as twisting, bending, squatting, flexing, and overhead reaching [11]. Finally, most technicians agreed that their job requires lifting heavy objects in awkward postures [11].

The risk of injuries is higher for small enterprises as compared to large companies. According to the Occupational Safety and Health Administration (OSHA) of Europe (2014) [12], small firms’ fatal accident rate is almost twice compared to that of larger ones. This increased injury rate could be due to a lack of care and regulations in the smaller enterprises [13]. Additionally, the lack of education for most workers in small enterprises and the willingness of these workers to work for long hours contribute to increased injuries [14].

Worldwide, few studies evaluated the risk of WMSD discomfort among automotive technicians. Moreover, to the best of the researcher’s knowledge, no study has investigated WMSD cases among this group of workers in Saudi Arabia (SA). Therefore, the current study aimed at evaluating the WMSD cases and the related physical and psychosocial risk factors among technicians who work in the small automotive repair shops in Jeddah, Saudi Arabia. Moreover, the current study aimed at assessing the body postures of automotive technicians and the associated WMSD risk level using the rapid upper limb assessment (RULA) ergonomic assessment tool [15].

2 Materials and method

2.1 Participants

The study employed a cross-sectional design. A total of 20 automotive mechanical repair shops in Jeddah, SA, were selected for this study. From the selected shops, 30 automotive technicians were asked to participate in the study voluntarily. To qualify as a participant, an individual should have worked as an automotive technician, at least in the last 12 months. Also, potential participants were excluded if they have had any WMSD symptoms due to previous accidents unrelated to their job as automotive technicians.

2.2 Materials

A weight scale was utilized to measure each participant’s body mass. The scale was placed on a flat surface in the working area, and the participant was asked to take the shoes off and step on the scale. Also, a stadiometer was used to measure the participant’s stature. The body mass and stature were recorded on the survey questionnaire of the participant. Body mass index (BMI) was estimated for each participant using the value of the body mass (in kg) divided by the body stature squared (in m²).

A 26-question survey and body parts discomfort diagram were created to evaluate WMSD symptoms and the potential risk factors among automotive technicians. At each shop, the technicians were gathered in a meeting and informed about the research objectives and data collection procedures. The technicians were told that the identity and information they would share would be confidential and for research purposes only. The researcher then distributed copies of the survey to the technicians. Also, The researcher read the questions to the technicians and made the required rephrasing to make sure they understood what is required in each question.

A smartphone was used to video record some of the technicians while they were performing various jobs for further postural analysis. Most of the technicians refused to appear on video, and thus, it was not possible to include all tasks in the postural analysis. A cloud-based ErgoPlus© software was installed on a Windows 10 laptop to analyze the video recorded tasks using RULA, the ergonomic postural assessment method developed in 1993 [15]. A free motion analysis software ‘Kinovea, version 0.8.15’ was used to measure angles of awkward body postures to accurately determine the body posture score, using RULA assessment via ErgoPlus© software.

2.3 Survey measurements

The survey included questions about the participant’s age, education level, dominant hand, and employment duration as an automotive technician. Also, there were questions about the daily shift and the break duration. Moreover, the survey included a question about the maximum weight the participant lifts or handles. To identify non-occupational exposures, information about after work activities that required muscular efforts was also obtained from each participant via the survey. It also included a question about the nature of the daily tasks the participants performed in the job, the body posture adopted while performing each task, and the duration to complete each of those tasks.

To evaluate the impact of their job duties upon their health, the participants were asked further questions via the survey. This included questions about the job and working environment satisfaction. The participants were required to rate their mental and physical exhaustion levels after work. They were asked to identify WMSD discomfort in their body parts using the body part discomfort diagram within the survey. Using this body diagram, each participant had to specify the body parts with pain or discomfort, rate the intensity level of said pain, and determine how often they felt it.

In order to assess the relation between working as a mechanic and having WMSD discomfort, the technicians were asked to identify the root causes for the pain or discomfort they had on each body part. They were also asked about the tasks they believed aggravated the pain or discomfort. Finally, the survey included a question about the number of days the worker missed due to injuries.

2.4 Survey validity

The face validity approach was used to test the validity of the developed survey and its appropriateness for collecting the required data. The researcher introduced the survey to three occupational safety and ergonomics experts to get their feedback on every part. The necessary modifications were considered, and the survey was updated accordingly.

2.5 Statistical analysis

Descriptive statistics (mean and SD) of age, stature, and body weight were used to describe the characteristics of the study population. The prevalence of pain in different body parts and the average level of pain intensity (out of 5) were estimated. Additionally, the prevalence of WMSD discomfort among the participants who missed days from work due to injury and participants who lifted heavy objects was estimated.

Pearson correlation test was conducted to examine the correlation between the dependent variables (i.e., pain rating for various body parts with WMSD discomfort prevalence >60%) and the independent variables. These independent variables included personal characteristics (i.e., age, BMI, employment duration, and education level) and job characteristics (i.e., maximum lifting weight and working hours). Pearson correlation coefficient’s various ranges include 0.00 to 0.19 (i.e., very weak correlation), 0.20 to 0.39 (i.e., weak correlation), 0.40 to 0.59 (i.e., moderate correlation), 0.60 to 0.79 (i.e., strong correlation), and 0.80 to 1.00 (i.e., very strong correlation).

2.6 Postural analysis

Rapid upper limb assessment (RULA) is a quick and easy-to-use ergonomic assessment tool utilized to evaluate the risk of musculoskeletal loading within the upper limbs and neck. The postural assessment of RULA is divided into two sections. The first section (i.e., section A) allows the user to analyze the arms and wrists postures. The second section allows for a neck, trunk, and leg postural analysis. Both sections allow the user to identify muscle use and force scores [15].

The final RULA score helps users identify the risk level of WMSD associated with the job being evaluated. A RULA score of 1 or 2 indicates that the WMSD risk is negligible, and the body postures are acceptable if not maintained for a long period. A score of 3 or 4 indicates that the WMSD risk is minimal, and further investigation and changes may be required to correct the body posture. A final RULA score of 5 or 6 indicates that the WMSD risk is moderate, the job needs to be investigated soon, and required changes need to be made in the short term to reduce the risk level. Lastly, a RULA score of 7 indicates that the job is associated with high WMSD risk, and thus, further investigation and changes should be made immediately [15].

3 Results

3.1 Personal characteristics

Thirty male automotive technicians who worked in small automotive repair shops in Jeddah, SA, participated in the current study. The mean (SD) age, body mass, and stature of the participants were 31.9 (7.4) years old, 77.9 (8.0) kg, and 169 (6.8) cm, respectively (see Table 1). Also, the mean (SD) of the estimated BMI was 27.3 (3.0) kg/cm². Figure 1 indicates that the education level for about half of the participants (n = 16, 53.3%) was secondary school, while the education levels for the rest of the participants were elementary (n = 5, 16.7%), intermediate (n = 7, 23.3%), and college (n = 2, 6.7%).

Table 1
Participants’ demographic and anthropometric information

Mean Std. deviation

Age 31.9 7.4

Body mass (kg) 77.9 8.0

Stature (cm) 169.0 6.8

	Mean	Std. deviation
Age	31.9	7.4
Body mass (kg)	77.9	8.0
Stature (cm)	169.0	6.8

Fig. 1

Education level.

The results showed that 19 participants (63.3%) stated that the right hand is the dominant hand, while 11 participants (36.7%) said that both right and left hands are their dominant hands. The responses to the question about the employment duration (Fig. 2) indicated that more than half of the participants (n = 18, 60%) have been working as technicians for >10 years. The rest of the participants stated that they have been working as technicians for the period of 5 < years ≤10 (n = 8, 26.7%) and the period of 1 < years ≤5 (n = 4, 13.3%) (Fig. 2).

Fig. 2

Employment duration.

3.2 Job characteristics

Furthermore, the results showed that more than half of the participants (n = 17, 56.7%) worked for more than 10 hours per working day (i.e., maximum of 14 hours) while the rest worked between 6 and 10 hours per working day (i.e., minimum of 8 hours). Additionally, the results showed that technicians are given break durations of 90 < minutes ≤120 (66.7%), 60 < minutes ≤90 (23.3%), and 30 < minutes ≤60 (10%) (Fig. 3).

Fig. 3

Break duration.

The results demonstrated that most participants (n = 20, 66.7%) lift or handle heavy objects at the workshop. The mean (SD) maximum weight is 55 (11.9) kg. Most participants (n = 26, 86.7%) stated that they do not perform any physical activities that require muscular efforts in their leisure time. On the other hand, only four participants declared that they perform muscular efforts in activities such as fitness exercises and playing soccer.

The participants listed various tasks they perform at work daily, the body postures while performing these tasks, and the time they spent on each task (see Table 2). These tasks include replacing brake pads and discs, control arms, shock absorbers, gearbox, engine mountings, spark plugs, installing a car engine and fuel tank, and engine overhaul. The common awkward body postures described by the participants and observed by the researcher include standing with the arms overhead, neck extension/flexion, trunk flexion and side bending, and wrist flexion/extension. The time required to perform these tasks ranged between thirty minutes to six hours (Table 2).

Table 2

Performed tasks, body postures, and duration

Task	Body posture	Duration
Replacing brake pads and discs	Wrist extension/twisting, upper arm flexion/abduction, trunk flexing/twisting, and squatting	0.5–1 hour
Replacing control arms	Standing with arms overhead, lower arms flexion, and wrist and neck side bending	1-2 hours
Replacing shock absorbers	Standing with arms overhead, neck extension, wrist flexion	2–5 hours
Replacing gearbox	Standing with arms overhead and neck extension	2–5 hours
Replacing engine mountings	Standing with arms overhead and neck extension or trunk and neck flexion (if working underneath the car)	2-3 hours
Replacing spark plugs	Trunk and neck flexion	0.5–1 hour
Installation of a car engine	Prolonged standing with trunk and neck flexion	4–6 hours
Installation of a fuel tank	Prolonged standing with arms overhead and neck extension	3–5 hours
Replacing axle boots	Standing with arms overhead and neck extension	2-3 hours
Engine overhauling	Trunk and neck flexion	2-3 hours

3.3 Potential impact

3.3.1 Psychosocial stress

Automotive technicians are expected to have increased psychosocial stress from the work requirements and workplace and tools limitations. In the current study, the participants stated that they are satisfied with their job as technicians and satisfied with the working environment. The responses indicated that the feeling of being mentally exhausted after work were as follows: never (n = 6, 20%), occasionally (n = 11, 36.7%), often (n = 9, 30%), and always (n = 4, 13.3%) (see Fig. 4). Additionally, according to the responses, the feeling of being physically exhausted after work were as follows: never (n = 4, 13.3%), occasionally (n = 15, 50%), often (n = 8, 26.7%), and always (n = 3, 10%) (Fig. 5).

Fig. 4

Perception of mental exhaustion.

Fig. 5

Perception of physical exhaustion.

3.3.2 Physical stress

Workers who are employed in jobs requiring muscular efforts, such as automotive technicians, are exposed to high physical loadings on the joints and muscles. The nature of their work requires excessive efforts to handle the assigned maintenance work. These increased muscular efforts on a daily basis increase the risk of WMSD discomfort. If WMSD symptoms are not carefully controlled, automotive technicians will be at an increased risk of permanent disability.

Findings from the current study showed that twenty-three (76.7%) of the participants experienced WMSD discomfort in the 12 months prior to the survey. Body parts with the highest prevalence of WMSD discomfort (i.e., >60%) (see Fig. 6) included lower back: right and left (n = 22, 95.7%), neck: right and left (n = 20, 87%), shoulders: right (n = 19, 82.6%) and left (n = 18, 78.3%), knees: right (n = 15, 65.2%) and left (n = 14, 60.9%), and hand/wrist: right (n = 14, 60.9%). Other body parts associated with WMSD discomfort can be viewed in Fig. 6.

Fig. 6

WMSD discomfort prevalence by body parts.

About forty-eight percent (n = 11) of the participants reported missing days from work during the said 12 months due to WMSD discomfort. LBP (low back pain) was the common reason for this. The mean (SD) number of days missed is 7.5 (7.8) days, ranging between 1 to 30 days.

3.4 Correlation

The association between the personal characteristics (i.e., age, BMI, employment duration, and education level) and job characteristics (i.e., maximum lifting weight and working hours) with the reported WMSD discomfort intensity rate was evaluated through the Pearson correlation test. Only body parts with a pain prevalence of more than 60% (i.e., shoulders, neck, low back, right hand/wrist, and knees) were included in the correlation test. Pearson correlation test in Table 3 shows significant (p < 0.01) positive correlation between: maximum lifting weight and LBP rating (strong; r = 0.638), maximum lifting weight and shoulder pain rating (moderate; r = 0.591), LBP and shoulder pain ratings (strong; r = 0.678).

Table 3
Pearson correlation between personal characteristics, job characteristics, and reported WMSD discomfort

Age BMI Maximum lifting weight Employment duration Working hours Break duration Education level LBP rating Shoulder pain rating Neck pain rating Hand/wrist pain rating Knee pain rating

Age 1

BMI 0.562^** 1

Maximum lifting weight 0.131 0.276 1

Employment duration 0.469^* 0.484^* 0.253 1

Working hours –0.136 –0.576^** –0.442^* –0.205 1

Break duration 0.140 0.262 –0.008 –0.193 –0.201 1

Education level 0.030 –0.242 –0.116 –0.151 –0.024 0.039 1

LBP rating 0.065 0.199 0.638^** 0.168 –0.107 0.079 –0.116 1

Shoulder pain rating 0.290 0.482^* 0.591^** 0.157 –0.435^* 0.441^* –0.037 0.678^** 1

Neck pain rating 0.223 0.166 0.272 0.051 0.006 0.164 –0.061 0.285 0.495^* 1

Hand/wrist pain rating 0.182 –0.058 0.116 –0.262 0.011 0.101 0.049 0.022 0.086 0.231 1

Knee pain rating 0.102 0.017 0.317 0.030 0.023 –0.300 –0.147 0.356 –0.033 0.270 0.275 1

	Age	BMI	Maximum lifting weight	Employment duration	Working hours	Break duration	Education level	LBP rating	Shoulder pain rating	Neck pain rating	Hand/wrist pain rating	Knee pain rating
Age	1
BMI	0.562^**	1
Maximum lifting weight	0.131	0.276	1
Employment duration	0.469^*	0.484^*	0.253	1
Working hours	–0.136	–0.576^**	–0.442^*	–0.205	1
Break duration	0.140	0.262	–0.008	–0.193	–0.201	1
Education level	0.030	–0.242	–0.116	–0.151	–0.024	0.039	1
LBP rating	0.065	0.199	0.638^**	0.168	–0.107	0.079	–0.116	1
Shoulder pain rating	0.290	0.482^*	0.591^**	0.157	–0.435^*	0.441^*	–0.037	0.678^**	1
Neck pain rating	0.223	0.166	0.272	0.051	0.006	0.164	–0.061	0.285	0.495^*	1
Hand/wrist pain rating	0.182	–0.058	0.116	–0.262	0.011	0.101	0.049	0.022	0.086	0.231	1
Knee pain rating	0.102	0.017	0.317	0.030	0.023	–0.300	–0.147	0.356	–0.033	0.270	0.275	1

^**Correlation is significant at the 0.01 level (2-tailed). ^*Correlation is significant at the 0.05 level (2-tailed).

Also, Table 3 shows significant (p < 0.05) positive correlation between shoulder and neck pain ratings (r = moderate; 0.495), BMI and shoulder pain rating (moderate; r = 0.482) and break duration and shoulder pain (moderate; r = 0.441).

Moreover, the results indicated significant (p < 0.01) negative correlation between BMI and working hours (moderate; r = –0.576), as well as significant (p < 0.05) negative correlation between maximum lifting weight and working hours (moderate; r = –0.442) and between working hours and shoulder pain rating (moderate; r = –0.435).

Table 4 includes the affected body parts and perceived root causes of the pain as explained by the participants. The participants related the pain in the upper back and shoulders to working with arms overhead height, as is the case while replacing shock absorbers or engine mountings. The surveyed workers associated the pain in both lower legs and feet with prolonged standing, as in the case of installing a car engine. Pain in the knees was related to a prolonged squatting posture as while replacing brake pads and discs. Furthermore, pain in the lower back and neck was linked to trunk and neck flexion, respectively, as in replacing the spark plugs. Arm pain was said to be caused by twisting the arms (i.e., supination and pronation) during tightening or loosening automotive parts (see Table 4). Finally, the participants linked wrist pain to awkward wrist postures such as wrist flexion, extension, pronation, or supination during tightening and loosening parts (see Table 4).

Table 4

Participants’ explanations for different causes of WMSD discomfort

Affected body parts	Causes
Upper back	Working with arms overhead height
Lower legs	Prolonged standing and squatting
Shoulders	Working with arms overhead height
Knees	Prolonged standing and squatting
Neck	Neck flexion, extension, side bending
Lower back	Trunk flexion and lifting heavy objects
Feet	Prolonged standing
Arms	Twisting arms during tightening and loosening parts
Wrist	Wrist flexion, extension, pronation, or supination

3.5 RULA

Some tasks were video recorded, including the replacement of brake pads and discs, control arms, shock absorbers, and spark plugs. A snapshot representing the awkward posture of each task was selected from each video for RULA assessment via ErgoPlus© software. Angles of awkward body postures were measured using Kinovea software.

Figures 7 and 8 show an example of the angle measurements of awkward body postures and the corresponding RULA assessment via ErgoFlow software, respectively, for replacing brake disc task. The RULA assessment resulted in a final RULA score of 7 for replacing control arms, spark plugs, brake pads and discs tasks. A RULA score of 7 indicates that body postures adopted by the technicians to perform these tasks impose high physical loadings on different body parts, and thus increase the risk of WMSD. Such a high score indicates that immediate changes need to be made to the tasks being performed in order to reduce the WMSD risk.

Fig. 7

Body angles measurements for disc replacement task.

Fig. 8

RULA assessment for disc replacement task.

The RULA assessment of the shock absorbers task resulted in a final RULA score of 6. A RULA score of 6 indicates that body postures adopted by the mechanic who performed this task impose high physical loadings on his body and increase the risk of WMSD.

Factors that increased the risk of the brake disc replacement task (i.e., high risk: RULA score of 7) include upper arm abduction, trunk flexion (>60°), trunk twisting, and forceful exertion to loosen the lug nut using the torque wrench (see Fig. 7). Similarly, reasons for the increased risk for brake pad replacement task include raising shoulders, wrist extension (>15°), neck flexion (>20°), neck side bending, trunk flexion (about 40°), and trunk side bending (see Fig. 9).

Fig. 9

Body angles measurements for brake pad replacement task.

Likewise, several issues played a role in the increased risk (i.e., RULA score of 7) of control arms replacement task, including upper arm abduction, raised shoulders, lower arms flexion (60°), wrist flexion (>15°), wrist side bending, and neck side bending (see Fig. 10).

Fig. 10

Body angles measurements for control arms replacement task.

The RULA assessment showed that the task of shock absorbers replacement was associated with a medium risk (i.e., RULA score of 6). Awkward body postures adopted by the mechanic while replacing the shock absorbers included upper arm flexion (>90°) and abduction, raised shoulders, lower arms flexion (>100°), wrist side bending, and forceful exertions (see Fig. 11).

Fig. 11

Body angles measurements for shock absorbers replacement task.

Finally, replacing spark plugs task showed a high risk of WMSD due to several awkward body postures, including upper arm flexion (45°–90°) and abduction, raised shoulder, wrist extension (>15°) and side bending, trunk flexion (>60°), neck flexion (>20°), and unbalanced legs (see Fig. 12).

Fig. 12

Body angles measurements for spark plugs replacement task.

4 Discussion

It is highly important to identify the physical factors (e.g., heavy loads and awkward postures) and psychosocial factors (e.g., mental exhaustion and job dissatisfaction) that negatively impact the health of automotive technicians. Failing to do so would leave these risk factors uncontrolled and thus increase the risk of WMSD discomfort. In worst-case scenarios, WMSD discomfort could lead to permanent disability. The results from the current study demonstrated that in the 12 months prior to the study, 76.7% of the participants experienced pain in several body parts, including the shoulders, neck, upper back, elbows, lower back, forearms, hips, hand/wrist, knees, thighs, lower legs, and ankles/feet.

4.1 LBP

The highest prevalence of WMSD discomfort reported by the participants was for the right and left sides of the lower back (95.7%). This finding is in agreement with the finding from Torp et al. [5], which demonstrated that the highest pain rating was for the lower back (76%). However, the LBP prevalence reported by Torp et al. [5] and Nasaruddin et al. [9] (i.e., 66.5%) is lower than the one reported in the current study. The high LBP prevalence in the current study could be due to the high BMI for most of the participants (mean = 27.3 kg/cm²). Nasaruddin, Tamrin [9] showed that about 37% of the participants were overweight (i.e., 25.0 < BMI <29.9). However, no information was reported by Torp et al. [5] about the participants’ BMI. Also, after the author’s discussion with the participants in the current study, it was apparent that they had low awareness about the proper ergonomics practices (e.g., proper lifting technique), which could be another factor contributing to high LBP prevalence.

High LBP prevalence was expected, for most of the technicians lift and handle heavy objects (e.g., vehicle engine and gearbox) and work in awkward body postures. The significance of lifting and handling heavy objects upon LBP risk has been commonly established over the past decades [16 –18].

Additionally, automotive technicians frequently bend their trunk during lifting or performing other tasks (e.g., replacing car engines or spark plugs). Several studies demonstrated that non-neutral trunk posture was associated with LBP [19 –21]. Internally generated forces, which are the results of external loadings from lifting and forces due to awkward body postures, aggravate the forces acting on the lower back, and thus, increase the risk of LBP.

The mean (SD) LBP intensity rated by the participants in the current study was 4.2 (0.9) out of 5, indicating the significance of LBP risk upon the technicians. Findings from Abaraogu, Ezema [10] showed that LBP had limited 50.3% of the technicians’ work activities. Similarly, the current study results indicate that 47.8% of the participants have missed, on average, 7.5 days from work due to LBP. Therefore, the researcher suggests that the technicians adjust the height of the work surface to prevent trunk flexion as possible. Also, the researcher recommends the technicians to work as close as possible to the working surface (i.e., reduce the horizontal distance between the worker and work surface) to reduce loadings upon the lower back. Finally, automotive repair shops are highly recommended to provide mechanical lifting equipment (e.g., hydraulic crane) to lift heavy objects such as engines or gearboxes instead of having workers perform such heavy lifting.

4.2 Neck/shoulder

The next highest prevalence of WMSD discomfort reported by the participants were for the right and left sides of the neck (87%) and shoulders (>78%). Nasaruddin, Tamrin [9] reported a slightly lower prevalence of neck (66.5%) and shoulder (69.1%) pain compared to those evidenced in the current study. A lower prevalence was reported by Torp et al. [5] for the neck (62%) and shoulders (52%). The high prevalence of neck and shoulders discomfort in the current study could also be attributed to the high BMI and lack of ergonomics awareness among the participants in the current study.

The mean (SD) intensity ratings for the neck and shoulders pain were 4.4 (0.7) and 4.0 (1.1), respectively. Several working conditions could be linked to the pain in the shoulders and neck, such as working on the car at overhead height with elevated arms and an extended neck. Automotive technicians are suggested to adjust the work surface’s height to be at chest level as feasible. The technicians are also recommended to take frequent breaks and avoid prolonged awkward working postures as possible in order to eliminate or reduce the WMSD discomfort.

4.3 Other body parts

The prevalence of knees and right hand/wrist pain were estimated to be more than 60%. Prolonged standing or squatting, as is the case when replacing the gearbox and the brake pads or discs, respectively, could be attributed to such a high prevalence of knee pain. Also, frequent awkward wrist postures such as flexion, extension, pronation, or supination could aggravate the wrist/hand WMSD discomfort, especially if these postures are adopted while handling heavy objects or tightening and loosening automotive parts, which require the worker to apply greater muscle forces to handle the job. It was demonstrated that frequent wrist flexion, extension, and sustained forceful movement were associated with carpal tunnel syndrome with odds ratios of 4.4, 2.7, and 2.6, respectively [22]. Thus, automotive repair shops are suggested to provide electric-powered hand tools to minimize automotive technician’s arm, wrist, and hand musculoskeletal efforts.

4.4 Psychosocial factors

The findings from the current study indicate that working as an automotive technician could be mentally exhausting in most cases. The study by Abdullah et al. [11] suggested that there was a significant association between the psychosocial factors and WMSD discomfort among the automotive technicians. However, in the current study, nearly all participants stated that they were satisfied with their job and working environment. The fear of losing the job could have influenced at least some of the job and working environment responses in the current study.

4.5 Correlation

The Pearson correlation test showed a significant (p < 0.01) strong positive correlation between maximum weight lifted and lower back pain ratings. The test also showed a significant (p < 0.01) moderate positive correlation between maximum weight and shoulder pain ratings. These findings support the statement that the heavier the load, the worse the lower back and shoulder symptoms.

The results also showed a significant (p < 0.01) strong positive correlation between the lower back and shoulder pain ratings. This correlation further demonstrates that most participants experienced pain at both the lower back and shoulder due to heavy lifting (i.e., >23 kg) and awkward working postures. These findings are in line with those by Nahit et al. [23], who showed that the manual handling of heavy objects and awkward body postures were associated with low back and shoulders pain.

Table 3 shows a significant (p < 0.05) moderate positive correlation between shoulder and neck pain ratings. This could be attributed to working conditions where technicians work with arms at overhead height while the neck is extended (i.e., backward bending), which could result in shoulder and neck pain due to elevated arms and extended neck, respectively. Findings from previous studies support findings from the current study regarding the impact of task requirements on neck and shoulder symptoms. It was demonstrated that overhead reaching increases the potential of shoulder injuries [24]. Another study showed that working with hands above shoulder level develops neck pain [25].

Moreover, the results showed a significant (p < 0.05) moderate negative correlation between working hours and shoulder pain rating. This could indicate that shoulder pain has minimized some technicians’ ability to work for extended hours. Similarly, a significant (p < 0.01) moderate negative correlation was found between working hours and BMI, in which individuals with higher levels of body fat tend to work for fewer hours. This may show that this group of technicians (i.e., high BMI) get fatigued quickly due to their unfit bodies and thus spend less time at work. This may contradict the findings from [26] that demonstrated that BMI was not associated with physical exertion among blue-collar workers.

Likewise, a significant (p < 0.05) moderate negative correlation was found between working hours and maximum lifting weight. Technicians who regularly lift heavier objects tend to work for fewer hours. This may express that technicians who lift heavy objects get fatigued earlier than those who do not, thus spending less time at work.

4.6 RULA

Findings from the current study support the claim that automotive technicians are exposed to high physical loadings. The performed RULA assessment’s outcomes showed that technicians who were assessed while replacing the brake pads and discs, control arms, and spark plugs were at high risk of WMSD due to the out-of-range body postures that they had to adopt. Also, the task of replacing the shock absorbers was assessed as a medium risk task. As a result, most participants reported WMSD discomfort in various body parts. Failing to minimize the exposure to physical stress such as heavy lifting, working with awkward body postures (e.g., trunk flexion, neck flexion, arm twisting), and prolonged standing could worsen the potential or existent WMSD discomfort and increase the risk of permanent disability. It is highly important to provide ergonomic training and education to automotive technicians to increase their awareness regarding safe working practices [27].

4.7 Limitations

Findings from the current study must be reviewed with respect to the following limitations. First, the study included thirty participants only. Including more participants could have shown different results. There were several reasons why it was not possible to include more participants in this study. Information about the total number of automotive technicians in Jeddah, SA, was not available through the official channels such as the General Organization for Social Insurance. In other words, no information about the population size was available to help determine the right sample size that reflects the population. Also, almost all automotive technicians in Saudi Arabia are residence (i.e., non-Saudi individuals). Five years ago, the government increased the residence permit card renewal fees to more than 100%, which may have resulted in more workers becoming unable to handle the living expense, and thus, leaving the country. Additionally, in the past five years, the government of Saudi Arabia has deported thousands of illegal immigrants. As a result of these actions towards the residence and the corrective actions towards the illegal immigrants, the number of automotive technicians has decreased, and numerous automotive shops were closed accordingly. Also, several automotive technicians refused to participate in this study. The reason could be due to the illegal residency of some of those technicians, and thus, their unwillingness to disclose their identity even though the researcher assured them that their identity and information they share are very confidential and will be used for educational and research purposes only.

Another limitation is fear of losing the job, which may have led some participants not to disclose all the information regarding their exposure to work-related ergonomic risk factors. As a result, the answers shared in this study may not fully show the correlation between the job and personal characteristics with the WMSD discomfort. Finally, the results presented here are based on subjective perceptions of the pain, which some participants could have overestimated or underestimated.

5 Conclusion and recommendations

It can be concluded that automotive technicians in Jeddah suffer WMSD discomfort in various body parts. Most of the technicians reported pain in the lower back, neck, shoulder, hand/wrist, and knees.

The prevalence of low back pain among the technicians was the highest compared with other WMSD symptoms. The workers explained that their job involves lifting heavy objects, prolonged standing, applying forceful movements using the hand/wrist, and working in awkward body postures.

The following is a set of recommendations for automotive technicians and owners to help reduce or eliminate the risk of WMSD discomfort:

Level the work surface height as feasible.

Get as close as possible to the working surface.

Prevent lifting heavy objects and use mechanical lifting aid instead.

Avoid prolonged standings and squatting.

Use electric-powered hand tools.

Provide ergonomics training sessions to the automotive technicians.

Conflict of interest

None declared.

Footnotes

Acknowledgments

The author would like to thank the automotive technicians for their valuable time devoted to participating in this study. The information they provided through the questionnaire and body part discomfort survey aided in better understanding the risk of WMSD discomfort among automotive technicians in Saudi Arabia.

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