Work-related musculoskeletal risk factors in medical laboratory students: A cross-sectional insights from a RULA-based assessment with lifestyle correlates

Work-related musculoskeletal risks in student laboratory settings are under-characterized. We conducted a cross-sectional study of 31 healthy male medical laboratory students to quantify upper-limb ergonomic risk using the Rapid Upper Limb Assessment (RULA) and examine associations with physical activity (International Physical Activity Questionnaire-Short Form), sleep quality (Pittsburgh Sleep Quality Index), quality of life (WHOQOL-BREF), and anthropometry. Standardized 5-min task videos were independently scored by three trained assessors. RULA scores clustered at mid action levels, indicating investigation and possible modification for most and prompt action for a notable minority. Across physical-activity strata, between-group differences for upper-arm posture (χ²(2) = 6.07, p = 0.04), the upper-limb composite Score A (χ²(2) = 7.69, p = 0.02), and the adjusted upper-limb composite Score C (χ²(2) = 6.35, p = 0.04), with the high-activity group generally exhibiting more favorable scores. In multivariable ordinal models, higher BMI predicted worse wrist-posture categories (OR = 1.33, 95% CI [1.02-1.73], p = 0.03), whereas PSQI, overall QoL, and IPAQ contrasts were not independent predictors of Score A or upper-arm posture. These findings identify upper-limb postural load as the predominant ergonomic concern and suggest anthropometric fit and movement behaviors as actionable targets. Given the small, single-site, male-only sample, results are preliminary; curriculum-embedded ergonomic adjustments (bench/eyepiece height, forearm support, micro-breaks) warrant evaluation in larger, mixed-gender, multi-site studies.