A physiological exploration on operational stance and occupational musculoskeletal problem manifestations amongst construction labourers of West Bengal,India

Abstract

BACKGROUND:

A huge number of labourers work in the construction industry in India both in organized and unorganized sectors. The construction labourers most often work for an extended period of time and they are compelled to uphold altered static and dynamic operational stance in awkward positions during the complete period of work which raises the demand on the musculoskeletal system and may lead to work related musculoskeletal disorders (WRMSDs).

OBJECTIVE:

This study is intended to explore the operational stance and occupation related musculoskeletal manifestations amongst the construction labourers. One hundred sixty four male labourers from different construction sites in West Bengal were randomly taken for this study.

METHODS:

A modified Nordic questionnaire on MSD and the 12 item General Health Questionnaire (GHQ12) were administered on the construction labourers. Rapid Entire Body Assessment (REBA) and Ovako Work Analysis System (OWAS) methods were applied to analyze the operational stance. Finally, discomfort levels of the specific operational stance were calculated by the use of risk level and BPD scale.

RESULTS:

The study revealed that most of the construction labourers habitually worked in awkward operational stance and were affected by altering musculoskeletal manifestations like pain in low back, neck, and wrist. We also found that there is a significant ( $p<$ 0.05) association between the intensity of pain feeling, age, year of working experience and risk level of the individual working postures of the labourers.

CONCLUSION:

Appropriate work-rest schedule, amendments of some working techniques and use of some ergonomically designed equipment may lessen the WRMSDs and improve the health eminence of construction labourers in unorganized sectors.

Keywords

Construction labourers operational stance risk level WRMSDs

1. Introduction

West Bengal is an eastern State in India, where a large number of labourers involved in construction work both in organized and unorganized sectors. Construction work is one of the major contributors to nation’s improvement which offers occupation and development of other comparable trades e.g. cement, painting, wood, electrical, hardware, etc. The constant use of manual handling of construction resources, working on elevated surface, lifting of materials, working beyond the capability and thermal load of working environment transform the construction work into a hazard [1].

About 4 million labourers are engaged in construction allied works in India [2]. There is a strong confirmation of the association between awkward position and musculoskeletal disorder [3]. The engagement in a construction zone is purely temporary, so it affects the relations between employer and employee a flimsy one. Work related operational stances may cause distress and strain on the musculoskeletal system of the construction workers [4, 5]. The duration of regular working hours are also accountable for the development of musculoskeletal complaints [6]. It was reported that static standing posture is concomitant with musculoskeletal prejudice [7].

The stance adopted by the labourers depends upon the type of work, the design of the workplace, personal characteristics, the tools required to perform the particular job and also upon the duration and frequency of the work cycle [8]. The labourers have always to negotiate with improper working stances. It has been documented that Indian economy is characterized by the existence of high levels of informal or unorganized labour engagement. The labourers in the organized sector constitute about 7% of the country’s total workforce and the rest (93%) belong to the unorganized counterpart [9]. WMSD is one of the most significant work-related health problems and most significant issue leading to the decreased work capacity of the construction labourers.

The WRMSDs have alarmingly increased in today’s world due to inappropriate knowledge among the labourers [10]. It also was observed that the discomfort increases with the advancement of age as aged people refuses to undertake new ideas of a modern workplace [11, 12]. Not only that, the knowledge of proper material handling as well as the physiologically suitable posture or stance is lacking in the developing countries and therefore the prevalence of musculoskeletal disorders is very obvious [13].

As per our findings, minimal research reports are present which could define the possible physiological vulnerabilities faced by construction labourers in India. Therefore, present study is designed to explore the operational stance and prevalence of occupational musculoskeletal manifestations amongst the construction labourers.

2. Material and methods

2.1 Subjects

Data were collected from 164 adult male construction labourers. To elude selection prejudice, all the subjects were arbitrarily taken from diverse work sites in the state of West Bengal. They were categorized in two groups (Group-A and Group-B) according to their working experience ( $<$ 10 years and $>$ 10 years, respectively). All the subjects were free from physical abnormalities and did not have any of the life threatening or communicable diseases ever. Consents were taken from the labourers to conduct the study.

2.2 Study of somatic characteristics

Height and weight of the subjects were measured by using Martin’s anthropometer and a standardized weighing machine, respectively. From these data, Body Surface Area (BSA) [14] and Body Mass Index (BMI) [15] were calculated.

2.3 Questionnaire study

Table 1
Somatic characteristics of the construction labourers ( $n=$ 164)

Characteristics	Years of experience		$p$	Interpretation
	Group A ( $n=$ 74)	Group B ( $n=$ 90)	value
	(Mean $\pm$ SD)	(Mean $\pm$ SD)
Age (Years)	34.62 $\pm$ 2.74	43.11 $\pm$ 3.02	0.0001	S
	(28–36)	(40–48)
Height (cm)	163.68 $\pm$ 4.46	164.28 $\pm$ 3.94	0.36	NS
	(159.3–165.6)	(158.8–166.9)
Weight (kg)	61.29 $\pm$ 7.03	60.47 $\pm$ 7.52	0.47	NS
	(57–63)	(56–61)
BMI (kg/m ${}^{2}$ )	23.31 $\pm$ 2.82	23.55 $\pm$ 3.20	0.61	NS
	(21.35–24.56)	(21.54–25.12)
BSA (m ${}^{2}$ )	1.69 $\pm$ 0.09	1.67 $\pm$ 0.09	0.15	NS
	(1.52–1.94)	(1.35–1.68)

Group-A and Group-B are based on the working experiences, i.e. $<$ 10 years and $>$ 10 years respectively; SD, standard deviation; S, statistically significant; NS, not statistically significant.

The postural stresses were assessed based on the modified Nordic Musculoskeletal Disorder Questionnaire (MSQ) [16]. The questionnaire constituted sequences of questions with multiple-choice answers. The questions were of two types in a broad – one part was accompanied with the various working manifestations and the other part contained of the queries about human physiological health. The questionnaire was conveyed to both the groups into the resident vernacular (Bengali and Hindi). The times of feeling maximum discomfort (i.e. morning or afternoon or evening or night) as well as the body parts with discomfort (neck, shoulder, low back, wrist/hand, leg, etc.) was also documented. The degrees of discomfort/pain of the labourers were evaluated using Body Parts Discomfort (BPD) [17] scale. The subjects were asked to assess their discomfort levels and the grade was accordingly given to the response of each individual.

In addition, the 12-item General Health Questionnaire (GHQ12) [18] was administered among the construction labourers to obtain data associated to their psychological distress owing to work. The General Health Questionnaire (GHQ) is a measure of existing mental well-being. The GHQ screens for non-psychotic psychiatric ailments. This questionnaire focuses on two major areas: 1) the inability to perform regular tasks and 2) the appearance of new and stressful phenomena. There are various systems that can be used to score this questionnaire. The system used to score the GHQ12 questionnaires in this study was the GHQ score method (0–0–1–1 method). Using this method, construction labourers could score between 0 and 12. A GHQ score of 4 or above specifies a high level of psychological misery.

2.4 Investigation of daily work schedule

The investigation of the daily work schedule of the construction labourers was carried out by uninterrupted surveillance through visual inspection and time measurement was done by using a stopwatch. Video recording was also done. Later, recorded videos were scrutinized and compared with data collected during direct surveillance from the work site for comprehensive and precise work-rest study.

2.5 Analysis of the operational stances

Rapid Entire Body Assessment (REBA) [19] and Ovako Working Posture Assessment System (OWAS) [20] were executed to determine the postural stress of the labourers in altered operational stances.

Four steps were conducted for analysis of working postures:

Step 1:
The working postures were recorded with the help of a digital camera (Nikon Coolpix L-810). Quite a few work cycles were recorded because operational stances can vary in different work cycles of the same job depending on the nature and demands of the job [21].
Step 2:
The most frequently repetitive operational stances or the postures that were held for the extended period of time of the work cycles were preferred for assessment.
Step 3:
The videos of the chosen operational stances were frozen and stick diagrams were made. After that, all joint angles and joint motion were evaluated and scoring was made.
Step 4:
Finally the grand score was compared to the action level list for assessing the risk level for a particular stance.

2.6 Statistical analysis

The data were expressed as mean $\pm$ standard deviation (SD). Comparisons of the means of different parameters of the construction labourers were made by student’s t-test, $p<$ 0.05 as a limit of significance. The Chi-square test was executed to evaluate the alteration of localization of pain among the labourers of the two separate groups. Level of significance for the test was taken as $p<$ 0.05 [22].

3. Results

The somatic characteristics of the construction labourers grouped according to the working experience have been presented in the Table 1. The $p$ value showed that age varied significantly between the two groups. Other variables did not show to have significant variation between two groups. In general, the more experienced labourers were aged and physically bulky than the less experienced counterpart.

The general average duration of working hours, the average duration of rest allowance and the total number of working days per week of the labourers were gathered from questionnaire and represented in Table 2.

Table 2
The average duration of working hours, rest allowance and weekly working days of the construction labourers

Duration of work per day (hrs.)	Duration of rest per day (hrs.)	Number of working days in a week
(Mean $\pm$ SD)	(Mean $\pm$ SD)	(Mean $\pm$ SD)
8.18 $\pm$ 0.99	1.02 $\pm$ 0.23	6.28 $\pm$ 0.53
(8–8.5)	(0.45–1.15)	(6–7)

Table 3

Discomfort feeling throughout the various progression of the day among the construction labourers

Discomfort feeling	Construction labourers ( $n=$ 164)				$\chi^{2}$	Interpretation
(pain) at different times	discomfort feeling				( $p$ value)
	Group A ( $n=$ 74)		Group B ( $n=$ 90)
	Number	Percentage	Number	Percentage
Pain felt during work	57	77.02	45	50.00	11.49 (0.0007)	S
Pain felt after work	14	18.91	12	13.33	0.58 (0.44)	NS
Pain felt before or after sleep at night	48	64.86	44	48.88	2.72 (0.09)	NS
Pain felt during 24 hours after work	16	21.62	11	12.22	1.970 (0.16)	NS

$\chi^{2}$ , Chi Square value, S, statistically significant; NS, not statistically significant.

Feeling of discomfort during various phases of the day amongst the construction labourers was presented in Table 3. The numbers of labourers complaining pain of both the groups was noted and chi square test was performed. It was detected that labourers of both the groups complained about feeling of pain during various day times. Amongst the responses, it was found that labourers complaining pain during working hours were significantly higher than those having pain after work, before or after sleep at night and 24 hours after the work.

Table 4 represents the percentage of annual discomfort/pain feelings in several body parts of the construction labourers classified according to years of experience as established by using modified Nordic questionnaire. The labourers complained that they used to feel pain in body parts like neck, shoulder, wrist, elbow, lower back and knees.

Table 4

Percentage of past one year discomfort/pain feelings in several body parts of the construction labourers

Parameters	Construction labourers ( $n=$ 164)
	Group A ( $n=$ 74)	Group B ( $n=$ 90)
Neck	34 (45.94%)	44 (48.88%)
Shoulder	28 (37.83%)	32 (35.55%)
Wrist	26 (35.13%)	34 (37.77%)
Elbow	19 (25.67%)	22 (24.44%)
Lower back	36 (48.64%)	78 (86.66%)
Knee	21 (28.37%)	26 (28.88%)

In Table 5, the association of past 12 months discomfort feeling of two groups of construction labourers was shown. The statistical analysis by the chi-square test and t-test was employed to assess the figure of construction labourers suffering from an analogous type of pain with years of experience correspondingly. In between the two groups lower back pain was significantly higher ( $p<$ 0.05) in the Labourers of Group B than the labourers of Group A.

Table 5

Association of past one year discomfort feeling of two groups of construction labourers

Body parts	Experiences	Feeling pain	Without pain	$\chi^{2}$ value	$p$ value	Interpretation
Neck	Group A	34	40	0.05	0.83	NS
	Group B	44	46
Shoulder	Group A	28	46	0.02	0.89	NS
	Group B	32	58
Wrist	Group A	26	48	0.04	0.85	NS
	Group B	34	56
Elbow	Group A	19	55	0.03	0.86	NS
	Group B	22	68
Lower back	Group A	36	38	25.93	0.0001	S
	Group B	78	12
Knee	Group A	21	53	0.005	0.94	NS
	Group B	26	64

Association of the past 12 month’s prevalence of occupational musculoskeletal manifestations in relation to different age and work tempo is presented in Table 6.

Table 6

Distribution of annual prevalence of musculoskeletal manifestations in relation to age and work tempo

Variables	MSD $(n=$ 114)	Without MSD ( $n=$ 50)	Total ( $n=$ 164)	$\chi^{2}$ value	$p$ value	Interpretation
Age
$<$ 40	36	38	74	25.93	0.0001	S
$\geqslant$ 40	78	12	90
Work tempo (Working hours per week)
$<$ 50 hours	42	30	72	8.49	0.0040	S
$\geqslant$ 50 hours	74	18	92

A breakdown of GHQ scores by occupational subgroup is provided in Table 7. This would specify comparable levels of psychological morbidity among the two groups of labourers.

Table 7

GHQ scores using a threshold value of 4

GHQ score	Group A ( $n=$ 74)	Group B ( $n=$ 90)
$<$ 4	36 (48.65%)	32 (35.55%)
$\geqslant$ 4	38 (51.35%)	58 (64.45%)

The association between GHQ scores using a threshold value of 4 and musculoskeletal manifestations are presented in the Table 8. Labourers with a GHQ of $>$ 4 reported higher prevalence of musculoskeletal manifestations than those with a GHQ score of $<$ 4.

Table 8

Relationship between GHQ scores using a threshold value of 4 and musculoskeletal symptoms

MSD	Group	GHQ	GHQ	$\chi^{2}$	$p$ value	Interpretation
symptoms		score $<$ 4	score $\geqslant$ 4	value
Yes	A	16	14	4.16	0.04	S
	B	22	52
No	A	20	24	0.76	0.38	NS
	B	10	06

Figure 1 shows the construction labourers feedback concerning to the feeling of pain in various body parts. The results have been integrated by applying the Body Parts Discomfort (BPD) scale.

Figure 1.

Comparative representation of Body Parts Discomfort (BPD) scale ratings of two groups of construction labourers.

Analyses of the most frequent operational stances as assessed by REBA and OWAS were presented in Table 9. All the construction labourers follow nearly the same pattern of postural changes while at work. It was clear that the majority of the stances were strenuous and their corresponding REBA and OWAS scores were high or very high.

Table 9

Analyses of the operational stances using REBA and OWAS

4. Discussion

The construction labourers have been doing this kind of work for years. They are bound to adopt some awkward operational stances for their work commitments at their work sites [5]. Musculoskeletal disorders are the collective physical ailments among these workers with an estimated 33% dominance in the general population and a frequency of 77% among construction workers. Musculoskeletal disorders not only impede productivity at work, they are also the foremost cause of sickness absenteeism, days of work lost and disability [24]. Construction related activities like carrying of sand, cement and brick, mixing of cement with sand, filling sand and cement mixture into the vessel by shovel and scoop, lifting iron materials from ground, burrowing soil by spade, etc. were too much stressful and tedious. The financial conditions of the labourers are poor and for that they have to work beyond their maximum aptitude. The work sites are not persistent and because of the dearth of knowledge about the human body, they are not alert of their possible vulnerabilities [23].

The construction labourers used to work for nearly eight hours in a day. It was observed that the labourers who had been engaged in this industry for a long time were more skilled and they had to handle the mighty, tenacious, unsafe and uncertain tasks. It was also noted that there was a significant difference between the ages of less and more experienced labourers. This was only because of their involvement in this industry for a long period of time.

The feelings of discomfort throughout the day were observed. However, the data indicated that the less experienced group felt maximum pain/discomfort during their work than the aged and more experienced group and the data was significantly ( $p<$ 0.05) higher for the inexperienced group, as indicated by the Students’ t test. Prolonged standing in altered static and dynamic stances and diverse awkward sitting postures imposes stress on the muscles that ultimately leads to fatigue. Scanty rest jeopardizes the situation. Likewise, the feeling of pain in the low back portion of the body among group B were also significantly ( $p<$ 0.05) more than the group A. The stressful and tedious jobs also impose strains on the regions like neck, waist, wrists and most forcefully on low back portion as pressure and movement of these body parts are directly involved during static or dynamic types of events [23].

From the Table 5, it can be concluded that there was a significant relationship between the stated low back pain differences between two groups of construction labourers according to their years of work experiences. Thus, experience (i.e. years of exposure) is one of the contributing factors for the prevalence or the progress of low back pain of the construction labourers. Statistical analyses (Table 6) revealed a highly significant correlation ( $p<$ 0.05) between the intensity of pain feeling and the repetitiveness on one low back, and the year of experience. This result proposed that highly repetitive works engaged for an extended time could increase the intensity of the pain felt and would lead to MSDs. From Table 6it also can be resolved that age and work tempo confirmed a significant association with musculoskeletal manifestations regarding occupation.

A breakdown of GHQ scores by occupational subgroup is provided in Table 7. This would specify similar levels of psychological morbidity between the two groups of labourers. In the total responders in group A 51.35% score greater than the threshold value of 4, whereas in group B 64.45% score greater than the threshold value. Labourers with a GHQ of $>$ 4 in group B reported higher occurrences of musculoskeletal manifestations than those with a GHQ score of $<$ 4 and this variance were statistically different (Table 8).

After observing discomfort or pain feeling in different body parts by using BPD scale during several activities it has been represented in the Fig. 1. This mean BPD rating have been done among the activities such as brick carrying, digging soil by spade, cement and sand mixing, lifting materials from ground, sand and cement bags carrying, sand loading into bucket by spade, filling mixture into the container by shovel, etc. The parts of possible discomfort are in the neck, waist, wrists, fingers and low back in the both groups. The construction labourers of both groups complained more about pain in lower back. These values are alarming in logic that these can cause severe damages in their lower extremities if this stature remains exposed for a long period of time.

It is remarkable that the stances the labourers adopt merely have any beneficial impact. Most of the stances are strenuous and the corresponding REBA and OWAS scores are alarming. Working stances accompanying with sand or cement bag carrying, filling mixture into the vessel by shovel, and lifting materials from ground- all of these postures belong to the high risk level with REBA and OWAS scores. Cement and sand mixing and loading it into vessel by scoop – all of these postures are belong to the very high risk level and amendment of those postures soon are exceedingly suggested. These working stances are likely to create extreme postural stress and also create extreme body parts discomfort or pain among the labourers because they repetitively bending in forward and backward, twisting, kneeling in sidewise and forward direction to complete their tasks. The impact of these strenuous postures on the labourers leads to produce occupation related musculoskeletal manifestations and followed by musculoskeletal disorders soon and implies serious health injuries. It is noteworthy that all the stances they have adopted are hazardous as well as unsafe and can enforce problems in the areas like vertebral column, which may disturb their work efficiencies and can ultimately impede the productivity.

The study was intended to assess whether the operational stances could damage the labourers’ wellbeing or not. The labourers reported to have pains in the various locations of the body. As per the study, it was found that the pain was due to excess strain in the shoulder, wrists, waist, low back and the limbs for long times. The assessment was done to establish the relation between the pains and the operational stances. It is clearly proved that the pains originate from the awkward postures and if it is maintained for a long period of time, the low back will face a great challenge. So an approach is essential for amending their stances instantaneously so that the labourers would be benefited at an earliest.

The exploration of working posture on this perspective is highly noteworthy as numerous of the people lives depending on these types of work in India. The physical, physiological and economical status of their living laid them in very constraint position. Along with that it is also noted, years of experience jeopardize their situation which may lead to different physical hazards which could exclude them from these jobs and ultimately could enforce a fatal situation upon them. Circumvention of strenuous postures, decrease of number of tedious work cycles, taking of micro breaks, improvement of stances through redesign of work methods upturn the productivity as well as their standards of physical, physiological and psychological health eminence.

5. Conclusion

From this study it was revealed that several cases were accountable for the occurrence of WMSDs among construction labourers. These factors are: high job demand, performance of repetitive awkward operational stances during at a stretch work in a sole work-rest cycle and insufficient rest-breaks opportunities.

Based on the investigation, it could be resolved that the construction labourers always perform in a very uncomfortable as well as uncooperative conditions because all the working activities in construction sites was very strenuous type of job in nature and different body parts has been affected from different awkward activities. So the labourers felt heavy stress during work and affected most of their body parts from different repetitive activities. Beside that it is likewise noted, years of experience endanger their condition which may prompt diverse physical vulnerabilities which could discard them from these occupations and eventually could implement a lethal circumstance upon them. From the results it is clear that the labourers severely develop work related musculoskeletal symptoms, especially in the lower back region. Along with that, the work sites are not properly organized and from this, any kind of deleterious accidents may always happen. Therefore, from ergonomic point of view construction labourers needs some ergonomic intervention in term of proper working circumstance to diminish their work stress and also to improve their quality of life.

Footnotes

Conflict of interest

The authors have no conflict of interest to report.

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