Original Research
Occupational Safety & Health

Assessment of Ergonomic Risk Level and Working Performance of Pre-Cast Construction Workers in Sabah

Background and Context

The construction industry consistently ranks among the most hazardous occupational sectors globally, and Malaysia is no exception. Construction workers face a constellation of ergonomic hazards including heavy manual lifting, sustained awkward postures, repetitive movements, whole-body vibration, and exposure to extreme environmental conditions. These exposures collectively drive high rates of work-related musculoskeletal disorders (WMSDs), which represent the leading cause of occupational disability and lost work time in the industry.

Precast construction — the fabrication of building components such as walls, beams, columns, and slabs in a factory setting before transportation to the construction site — has been promoted in Malaysia as a safer alternative to traditional on-site construction. The Malaysian government’s push toward Industrialised Building Systems (IBS) reflects an expectation that prefabrication can reduce on-site hazards, improve quality control, and address the construction industry’s chronic labour shortage. However, the precast manufacturing process itself involves substantial physical demands: workers must handle heavy moulds, pour and vibrate concrete, strip formwork, and manoeuvre completed components — all of which impose significant ergonomic stresses on the musculoskeletal system.

Sabah, located in Malaysian Borneo, has a construction sector that relies heavily on a workforce including both local and migrant workers. Occupational health surveillance and ergonomic assessment in Sabah’s construction industry have been limited, creating a knowledge gap that this study sought to address. The research is particularly valuable because it examines the relationship between objectively measured ergonomic risk exposure and worker performance outcomes — an association that has practical implications for both worker welfare and employer productivity.

Study Design and Methods

This cross-sectional study was conducted over six months (June to November 2014) at precast construction facilities in Sipitang, a district in the Interior Division of Sabah. All 116 male precast construction workers at the study sites were recruited, ensuring complete enumeration rather than sampling.

The study employed a multi-method assessment approach. First, structured interviews using a modified Standardized Nordic Musculoskeletal Questionnaire (SNQ) were conducted with each worker to establish the prevalence and anatomical distribution of musculoskeletal complaints. The SNQ is a validated, widely-used instrument that systematically captures the occurrence of musculoskeletal symptoms across nine body regions over specified time periods.

Second, ergonomic risk was assessed objectively using the Rapid Entire Body Assessment (REBA) tool. Photographs and video recordings of workers performing their routine tasks were captured and subsequently analysed by trained assessors. REBA generates a composite score reflecting the postural loading on the trunk, neck, legs, upper arms, lower arms, and wrists, with additional adjustments for load weight, grip quality, and activity type. Scores are categorised into risk levels: Negligible (score 1), Low (2–3), Medium (4–7), High (8–10), and Very High (11–15), each associated with recommended action levels ranging from no action to immediate investigation and change.

Third, individual working performance was assessed through employment records documenting overtime tendency and unpaid leave frequency over the study period. Pearson correlation and one-way ANOVA were used to test associations between ergonomic risk levels and these performance indicators.

Principal Results

The musculoskeletal disorder burden was alarmingly high: 80.17% of workers reported experiencing aches, pain, or bodily discomfort during or after work. The anatomical distribution of complaints reflected the specific physical demands of precast construction work. The high prevalence of wrist disorders (78.5%) corresponds to the repetitive gripping, twisting, and vibratory forces involved in handling formwork, operating vibrating compactors, and using hand tools. Shoulder complaints (73.1%) align with the frequent overhead reaching and sustained arm elevation required during mould assembly and concrete pouring. Lower leg disorders (71.0%) reflect the prolonged standing, walking on uneven surfaces, and crouching positions that characterise the work environment.

The REBA analysis produced equally concerning results: not a single worker was classified at low or negligible ergonomic risk. More than 43% of the workforce fell into the high or very high risk categories, indicating that their routine working postures warranted immediate ergonomic investigation and corrective action. This finding strongly suggests that the physical demands of precast construction work, as currently organised at these facilities, exceed the biomechanical capacity of the workforce to sustain without musculoskeletal injury.

The correlation between ergonomic risk level and working performance revealed a significant negative relationship. Workers exposed to higher ergonomic risk levels were less willing to work overtime (p<0.001, r=−0.55), suggesting that the cumulative physical burden of their regular work shifts left them unwilling or unable to extend their work hours. Conversely, higher risk exposure was positively correlated with the frequency of unpaid leave (p=0.038, r=0.56), indicating that ergonomic hazards translated into lost workdays — likely reflecting either inability to attend work due to pain or informal absenteeism driven by chronic discomfort.

Implications for Occupational Health Policy

These findings have substantial implications for occupational health regulation in Malaysia’s construction sector. The Department of Occupational Safety and Health (DOSH) Malaysia has published guidelines on ergonomic risk assessment, but enforcement in the construction industry — particularly at smaller precast operations in less urbanised states like Sabah — remains challenging. The universal elevation of ergonomic risk observed in this study suggests that passive compliance with existing guidelines is insufficient; active intervention programmes including job rotation schemes, mechanical handling aids, ergonomic task redesign, and worker training in safe lifting techniques are urgently needed.

For employers, the demonstrated link between ergonomic risk and lost productivity through reduced overtime willingness and increased absenteeism provides an economic rationale for investing in ergonomic improvements. The cost of musculoskeletal disorders — encompassing medical treatment, workers’ compensation claims, productivity losses, and recruitment costs for replacement workers — typically far exceeds the cost of preventive ergonomic interventions.

Limitations

The cross-sectional design prevents definitive causal conclusions about the direction of the risk–performance relationship. The study was conducted at a single geographic location in Sabah, and results may not be generalisable to all precast facilities nationwide. Self-reported musculoskeletal symptoms may be subject to recall bias and cultural factors affecting symptom reporting. Performance was assessed using employment records (overtime and leave) rather than direct productivity measures such as output per hour. Additionally, the study did not control for potential confounders including worker age, years of experience, body mass index, pre-existing health conditions, or psychosocial factors that may independently influence both musculoskeletal complaints and work performance.

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