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

Abstract 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.