Comparison of Work-Related Musculoskeletal Symptoms Between Quay and Rubber-Tyred Gantry Crane Operators: A Cross-Sectional Study.

BACKGROUND AND AIMS: Work-related musculoskeletal disorders (WMSDs) are a major global occupational health concern. Port crane operators are particularly susceptible due to the extremely awkward postures required at their workstations; however, comprehensive data on this specific population remain limited. This research aimed to investigate and compare the prevalence of work-related musculoskeletal (MSK) problems and perceived discomfort among operators of quay and rubber-tired gantry (RTG) cranes at the Laem Chabang Deep-Sea Port in Thailand. METHODS: A modified, standardized version of the Nordic Musculoskeletal Questionnaire (NMQ), incorporating a Borg rating scale, was administered to 26 male crane operators (11 quay and 15 RTG). An a priori power analysis using G*Power confirmed that a minimum sample size of 24 was sufficient for hypothesis testing. RESULTS: The NMQ revealed the lower back as the most commonly affected body part (76.9%), followed by the neck, shoulders, and upper back (each at 23.1%) across all port crane operators. Overall, 96.2% of participants reported MSK problems over the past 12 months. Borg scale ratings for perceived discomfort also showed the highest score for the lower back (2.38), followed by the upper back (0.65), shoulders (0.54), and neck (0.50). Notably, when comparing MSK prevalence (χ2 test) and perceived discomfort levels (Kruskal-Wallis test) across nine body regions between the two groups, a significant difference was found in the upper back; quay crane operators reported significantly more problems than RTG operators (p < 0.05). CONCLUSION: Factors such as awkward working postures, mental stress, working at height, trolley distance, and vibration are potential key contributors to these MSK issues. The significant difference in upper back problems suggests that quay crane operators face a greater magnitude of exposure to ergonomic hazards than RTG operators. Targeted interventions, particularly the implementation of engineering controls at workstations, are crucial to mitigate these occupational risks.