Evaluation of the influence of education on the ergonomic risk of concrete form workers

Abstract

BACKGROUND:

In developing countries, construction is a largely manual job that imposes awkward postures on workers, thus facilitating a variety of musculoskeletal disorders. Ergonomic training is known as an effective way to reduce these disorders.

OBJECTIVE:

This study aimed to evaluate the effectiveness of ergonomic training intervention in reducing the ergonomic risk of concrete form workers.

METHODS:

This quasi-experimental study was carried out on 144 concrete form workers employed in the construction projects of Gonbad-e Kāvus, Iran, Iran. Data was collected using the Nordic Musculoskeletal Questionnaire (at the pre-intervention stage) and the Rapid Entire Body Assessment (REBA) worksheet (at the pre- and post-intervention stages). Ergonomic training was provided via face-to-face educational meetings along with presenting informative pamphlets, which took place over 45 days duration of time. Data were analyzed by the use of SPSS software version 21, t-test and Wilcoxon test. Significant level was considered at P-value less than 0.05.

RESULTS:

Musculoskeletal disorders were observed in all limbs of the studied workers. The most prevalent disorders were the pain in the shoulder region of lift operators (86.1%) and the pain in the back area of mixer operators (77.8%). About 99.3% of all concrete form workers were exposed to a moderate level of ergonomic risk and needed posture correction. Pre- and post-training REBA scores showed a statistically significant difference (P < 0.05).

CONCLUSION:

Although the ergonomic training did reduce the ergonomic risk of workers, because of its short duration, it failed to reduce this risk to an acceptable level. It is recommended to hold both theoretical and practical training sessions over longer periods of time.

Keywords

1 Introduction

In developing countries such as Iran, the majority of construction jobs are manual works that rely on physical strength [1] and force the worker to remain in certain postures for long periods of time. Many of these jobs lead to Work-related Musculoskeletal Disorders (WMSDs) [2], which typically involve the lower back, spinal cord, and upper limbs [3]. Being among the most prevalent occupational diseases, these disorders are the leading cause of worker disability and affect millions of workers every year [1, 4]. Construction workers suffer from about 16% higher rate of WMSD than other industrial workers [5].

The construction of reinforced concrete (RC) structures requires a team of skilled and unskilled workers including steel fixers, formwork carpenters, mixer operator, lift operator, and wheelbarrow workers. Considering the typical physical requirements of construction jobs, such as manual lifting and handling of heavy loads (e.g. cement bags and rebars), bending and twisting of the body, working above shoulder height, working under knee height, and repetitive movements, construction worker are very susceptible to musculoskeletal disorders [6, 7]. Steel fixer and formwork carpenters rely on the forceful and repetitive twist of hand to fasten the rebars and formworks, which leads to hand and wrist disorders. In addition, these workers must often bend to work on the objects positioned below their knee level, which raises the ergonomic risk of their occupation [8]. It is known that the physical processes of construction works typically cause severe ergonomic problems [9]. Every construction worker is likely to do at least a portion of his work in awkward postures that result in notable physical damage or health implications during and after the job [9 –11].

Nasl-Saraji et al. reported that Iranian construc-tion workers have a high rate of musculoskeletal disorders and emphasized the need for ergonomic interventions and posture corrections [1]. The results of the longitudinal study among the Washington wor-kers showed that WMSD claim rates was declined from 1999 to 2013, but over 40% of all compensable claimswas due to WMSD, and construction works were identified High risk industries [12]. A study by Hecker et al. found that 72% of people who were involved in construction industry jobs in the past 12 months, had musculoskeletal disorders in at least one part of their bodies, and 66% of them believed that ergonomic training has had a positive effect on their work patterns [13]. Several studies have examined the impact of health and safety training on workers [14, 15]. A study by Kim has also asserted that training is essential for expanding the knowledge, raising the awareness, and improving the skills of workers [9].

Construction is a dangerous industry with a high risk of ergonomic damage. Thus, ergonomic training is imperative for the well-being of construction workers [8]. Construction of small RC structures is still a major part of the construction industry [13]. In Iran, the steady growth of population and housing needs has long reinforced the economic feasibility of private small-scale construction projects, which has led to the employment of many workers in this part of the construction industry. Considering the reputation of ergonomic training as an economic mean of reducing musculoskeletal disorders [16], this study aimed to investigate the effect of ergonomic training on the Iranian concrete form workers who work in small-scale RC construction projects.

2 Methodology

2.1 Research design and participants

This quasi-experimental study was carried out on 142 concrete form workers of small-scale reinforced-concrete construction projects in the city of Gonbad-e Kāvus (Gorgan Province, Iran) in 2015-2016. The sample was formed at random. The sampled population consisted of four workgroups: mixer operator, wheelbarrow worker, lift operator, and steel fixer. The inclusion criteria were to have at least one year of work experience, no history of surgery and musculoskeletal incident, and no history of musculoskeletal or congenital defects. After checking the inclusion criteria, the participants were fully briefed about the purpose of the research.

2.2 Methods

Data collection consisted of two sections: the first section was related to musculoskeletal problems using the Nordic Musculoskeletal Questionnaire (NMQs) and the second part included ergonomic risk assessment by Rapid Entire Body Assessment (REBA) method.

The NMQs was developed by Kuorinka et al. in order to analysis the epidemic of musculoskeletal problems. It includes 4 parts of general questions, limb musculoskeletal complaints (neck, shoulders, elbows, hands/wrists, back, buttocks/thighs, knees and ankles/legs), work absenteeism and working restrictions resulting from these problems. The Cronbach’s alpha for this scale was determined to be 0.905 [17]. To prevent possible mistakes, the questionnaire was filled by the researchers while asking the workers about the symptoms of musculoskeletal disorders.

The ergonomic risk in working people was evaluated with the help of Rapid Entire Body Assessment (REBA) worksheet. The REBA method was planned by Hignett and McAtamney in 1998 for the analysis of working postures [18]. In the REBA worksheet, the analysis of body segments is divided into two sections A and B. Section A covers 60 combined postures of trunk, neck, and leg, while Section B covers 36 combined postures of arms, forearms, and wrists. First, scores of Sections A and B must be determined according to body angles and positions as instructed in the worksheet’s score tables. Then, a force score must be applied to represent the effect of the force exerted while performing the work. Another score must also be applied to represent the effect of grip force required to handle the work tool while maintaining the work posture. After applying a final score to represent the effect of repetitive work activities, the final score of the REBA method will be obtained. This score, which is a value between 1 and 15, represents the ergonomic risk level of the worker and constitutes the basis of recommended posture correction measures. These scores are listed in Table 1 [18]. For this purpose, the researchers observed the work postures of participants and then classified and scored the observations using the REBA worksheet.

Table 1
Risk level of REBA score among the studied construction workers

Score Risk level Ergonomic action

1 Negligible No action required

2-3 Low Change may be needed

4-7 Medium Further investigation, change soon

8-10 High Investigate and implement change

11-15 Very high Implement change

Score	Risk level	Ergonomic action
1	Negligible	No action required
2-3	Low	Change may be needed
4-7	Medium	Further investigation, change soon
8-10	High	Investigate and implement change
11-15	Very high	Implement change

2.3 Intervention

For ergonomic education, workers attended an 8-hour training course consisting of theoretical and practice sessions held by occupational health experts at their workplace. The number of people attending each session varied depending on the number of workers at the site. In these sessions, workers were educated about the potential implications of abnormal work postures, the recommended postures for their work, and the proper way of handling heavy loads. After the training, then each worker was provided with an educational pamphlet, which reiterated the material covered in the sessions. After 45 days of education, the participants were again studied for the second time, and the risk level of REBA was evaluated.

2.4 Data analysis

The collected data were analyzed in SPSS (version 21, SPSS Inc., Chicago, IL, USA) using the t-test and the Wilcoxon test. Quantitative and qualitative data were stated as mean±standard deviation(SD) and frequency (percentage), respectively. Significant level was considered at P-value less than 0.05.

3 Results

All participants in this study were male. As shown in Table 1, the participants were mostly young adults with a mean age of 31.03 years and mean work experience of 5.15 years.

The highest rate of musculoskeletal disorder was observed among lift and mixer operators. More specifically, 86.1% of lift operators were suffering from pains in the shoulder area and 77.8% of mixer operators had back pains. The least prevalent disorders were the hip and ankle pain in steel fixers (2.7%) and the ankle pain in mixer operators (2.7%). Table 2 shows the prevalence of musculoskeletal disorders among different workgroups in the studied population.

Table 2
Demographic information of the participating workers

Variable Steel fixer Mixer operator Lift operator Wheelbarrow worker

Age (years) 30.86±7.53 31±6.92 30.55±6.77 31.72±7.30

Height (cm) 172.36±5.32 169.91±6.29 171.44±6.93 172.63±7.75

Weight (kg) 70.91±9.48 66.75±9.37 69.8±9.09 67.75±10.01

Work experience (years) 4.58±2.45 5.25±2.83 4.61±1.97 6.16±3.58

Variable	Steel fixer	Mixer operator	Lift operator	Wheelbarrow worker
Age (years)	30.86±7.53	31±6.92	30.55±6.77	31.72±7.30
Height (cm)	172.36±5.32	169.91±6.29	171.44±6.93	172.63±7.75
Weight (kg)	70.91±9.48	66.75±9.37	69.8±9.09	67.75±10.01
Work experience (years)	4.58±2.45	5.25±2.83	4.61±1.97	6.16±3.58

As shown in Table 3, most of the studied workers were exposed to a moderate level of ergonomic risk (REBA score of 4–7), which needs to be addressed with proper posture correction measures. Before the training, all workers in all workgroups, except 2.8% of steel fixers, had a moderate level of ergonomic risk. After the training, 22.2% of mixer operators, 25% of lift operators, and 27.7% of wheelbarrow workers shifted to a low (acceptable) ergonomic risk level, but the ergonomic risk of steel fixers remained unchanged.

Table 3

Prevalence of musculoskeletal complaints in the last 12 months among the studied construction workers n(%)

Body part	Steel fixer	Mixer operator	Lift operator	Wheelbarrow worker
Neck	14(38.9)	12(33.3)	15(41.7)	11(30.6)
Shoulders	21(58.3)	13(36.1)	31(86.1)	25(69.4)
Elbows	9(25)	9(25)	19(52.8)	27(75)
Hands and wrists	17(47.2)	15(41.7)	16(44.4)	25(69.4)
Back	27(75)	28(77.8)	16(44.4)	26(72.2)
Waist	18(50)	24(66.7)	12(33.3)	25(69.4)
Buttocks and thighs	1(2.8)	7(19.4)	6(16.7)	9(25)
Knees	13(36.1)	17(47.2)	10(27.8)	11(30.6)
Legs and ankles	1(2.7)	1(2.7)	6(16.7)	6(16.7)

According to the t-test results presented in Table 4, the mean ergonomic risk score of steel fixers de-creased from 5.91 before the training to 4.94 after the training (P < 0.05). The mean score of mixer operators also decreased from 5.52 before the training to 4.41 after the training (P < 0.05), and the mean score of lift operators decreased from 5.38 before the training to 4.02 after the training (P = 0.001). The greatest drop in the mean score, however, was observed among wheelbarrow workers, where this value decreased from 5.63 before the training to 3.77 after the training (P < 0.05).

Table 4

Ergonomic risk level of the studied construction workers before and after the ergonomic training

Working group	Risk level before training (%)			Risk level after training (%)
	Low	Medium	High	Low	Medium	High
Steel fixer	0(0)	35(97.2)	1(2.8)	0(0)	35(97.2)	1(2.8)
Mixer operator	0(0)	36(100)	0(0)	8(22.2)	28(77.8)	0(0)
Lift operator	0(0)	36(100)	0(0)	9(25)	27(75)	0(0)
Wheelbarrow worker	0(0)	36(100)	0(0)	10(27.7)	26(72.3)	0(0)

Table 5

Mean REBA score of the studied construction workers before and after the ergonomic training

Working group	Before training	After training	P-value
Steel fixer	5.91	4.94	<0.05
Mixer operator	5.52	4.41	<0.05
Lift operator	5.38	4.02	0.001
Wheelbarrow worker	5.63	3.77	<0.05

4 Discussion

The exposure of workers to ergonomic risk factors can be effectively mitigated by training and education programs [19]. This study aimed to investigate the effect of training on the ergonomic risk of the concrete form workers of small-scale RC construction projects. The results of ergonomic intervention showed that training alone could not significantly reduce the ergonomic risk of the studied workers. The cause of this poor impact can be related to work conditions, which make it difficult to adherence to recommended postures during work. Furthermore, in many cases, workers are required to complete their task at a fast pace, which forces them to take awkward postures [20 –22].

In this study, musculoskeletal disorders were surveyed using the NMQs. The NMQs results showed that irrespective of their workgroup, all studied workers had suffered from at least one disorder during the past 12 months, mostly in their back. The most prevalent musculoskeletal disorders among steel fixers were in the waist area (75%) and then the shoulders (58.3%). This can be related to the work condition of these workers, which requires them to stand and sometimes work above their shoulder height. The study of Nasl-Saraji et al. on construction workers also reported the highest prevalence of disorders in the waist and shoulders [1]. Among mixer operators, the most prevalent disorders were in the waist (77.8%) and the back (66.7%), which can be caused by standing for long periods of time and inappropriate handling of heavy loads. It is worth noting that construction workers are generally required to perform demanding physical tasks and repetitive movements and endure awkward work postures, which are very likely to lead to high rate of musculoskeletal disorders [20].

Here, lift operators showed a high rate of musculoskeletal disorders in the shoulder (86.1%) and the elbows (52.8%), which can be attributed to the fact that they often work above shoulder height. In a study by Gangopadhyay et al., 77% of stone cutting workers were suffering from a disorder in the shoulder region, which indicated that shoulders are subject to excessive stresses during the stone cutting operation [5]. In the study of Ludewig and Borstad, holding hands above shoulders and repetitive movements were identified as the causes of work-related shoulder disorders [23]. The study of Nasl-Saraji et al. reported a very low prevalence (4.5%) of elbow disorder among workers, which is not consistent with our results [1]. Most likely, the work of the subjects of that study did not require them to hold their elbows in a awkward and static posture.

According to our results, the wheelbarrow workers were mostly suffering from disorders in the elbow (75%) and the waist (72.2%), which is likely because of them having to handle heavy loads and endure awkward postures.

The study of the work postures of the studied workers with the REBA method showed that most of these workers are exposed to a moderate level of ergonomic risk, and it is imperative to implement proper ergonomic measures and interventions to correct their body postures. This result is consistent with the results of Habibi et al. [24] and Hajaghazadeh et al. [25], who suggested that ergonomic interventions are an essential necessity for occupations such as steel fixing and concreting.

After the ergonomic training, a significant decrease was observed in the ergonomic risk level of mixer operators, lift operators, and wheelbarrow workers, which indicated the effectiveness of training for these workgroups. However, no decrease was observed in the risk level of steel fixers. This is perhaps because of the nature of this work, which requires the person to work in several working postures. Considering the high prevalence of musculoskeletal disorders and high ergonomic risk of steel fixers, a more suitable work environment seems to be an absolute necessity for the well-being of these workers. A study by Mohammadi Zeidi et al. has confirmed the effectiveness of ergonomic training in the correction of physical postures [26]. But the study of Yaghobee has reported that ergonomic training has little impact in this regard [27]. Although our ergonomic training did reduce the ergonomic risk score, it failed to reduce the mean scores of mixer operators, lift operators, and steel fixers to an acceptable level (only the mean score of wheelbarrow workers was reduced to a low level). This is perhaps because our training was concentrated in two sessions help over a short period of time. Nevertheless, the impact of this training in reducing the ergonomic risk cannot be ignored [28]. If properly implemented, such training can be a viable solution for reducing musculoskeletal disorders [29].

5 Limitations

One of the limitations of this study was the lack of financial resources to design a proper environment, tools, and equipment in conjunction with our intervention. Further studies with the goal of examining the work tools and providing ergonomic suggestions for tool design may contribute to improving work posture and reducing the ergonomic risk of construction workers. Educating the workers about the proper ways of lifting heavy loads can also be effective in this regard.

6 Conclusion

The results of this study showed the high prevalence of musculoskeletal complaints among the concrete form workers of small-scale reinforced concrete construction projects. Most of the studied workers were found to need posture corrective measures. Although an ergonomic training provided by an occupational health professional did reduce the ergonomic risk of workers, it failed to reduce this risk to an acceptable level. In other words, even after training, most workers remained exposed to a moderate level of ergonomic risk. Considering the results, it is suggested to hold theoretical and practical courses over longer periods of time, or even make the ergonomic training mandatory to protect the long-term wellbeing of these hard-working people.

Conflict of interest

The authors declare that there is no conflict of interests.

Ethical approval

All procedures performed in accordance with the ethical committee of Gonabad University of Medical Sciences, Iran.

Funding

This study was supported by Gonabad University of Medical Sciences, grant no. 97/21.

Footnotes

Acknowledgment

The authors would like to thank the concrete form workers of Gonbad-e Kāvus in Iran and all the subjects who cooperated in the implementation of the research.

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