Improving Work Performance in Traditional Forging: A Study of Environmental Heat and Task-Related Ergonomic Factors

BACKGROUND: Productivity in traditional iron forging is strongly influenced by environmental heat, heavy physical workload, and poor ergonomic practices. In Bali's forging sector, workers are consistently exposed to intense radiant heat, repetitive manual tasks, and inadequate work–rest schedules, all of which contribute to physiological strain and musculoskeletal disorders (MSDs). OBJECTIVE: This study aims to evaluate the combined effects of environmental heat stress, task-related physical load, and organizational work patterns on worker health and productivity. An integrated ergonomic model was developed to examine how thermal exposure, workload intensity, rest duration, and MSDs interact to influence performance in traditional forging activities. METHODS: A cross-sectional study was conducted involving 280 male forging workers aged 21–52 years with 2–9 years of work experience. Physiological indicators—including body mass index (BMI), pulse rate, body surface temperature, and MSD scores—were measured before and after work. Environmental heat exposure was assessed using the Wet Bulb Globe Temperature (WBGT) index. Productivity was evaluated through workers' pulse response during activity and MSD-related discomfort. A Structural Equation Modeling (SEM) approach was employed to analyze pathways linking ergonomic risks to productivity outcomes. RESULTS: Productivity showed a significant decline in relation to task demands, including workload (β = –0.075) and MSD scores (β = –0.110). Organizational factors, particularly prolonged work duration (β = –0.105), further reduced performance, highlighting the importance of structured work–rest cycles. Environmental conditions exerted the strongest negative effect on productivity, with WBGT (β = –0.694) and body surface temperature (β = –0.101) indicating substantial thermal strain (WBGT 29.8℃–30.7℃; post-activity temperature 38.7℃–41.1℃).