Association Between Bag Weight and Shoulder Disabilities Among Medical College Students

Abstract

Background: Shoulder pain and disability are increasingly reported among university students, particularly those in academically demanding programs requiring routine carriage of heavy bags. Repetitive load carriage may impose mechanical stress on the shoulder complex, potentially leading to functional impairment; however, evidence specific to medical undergraduates remains limited. Objective: To determine the association between bag weight and shoulder pain and disability among medical college students. Methods: An analytical cross-sectional study was conducted among 340 undergraduate medical students aged 18–24 years from two medical colleges in Lahore. Bag weight (kg) and relative bag weight (% body weight) were measured using calibrated scales. Shoulder pain and disability were assessed using the validated Shoulder Pain and Disability Index (SPADI, 0–100 scale). Group comparisons were performed using independent t-tests, and associations were evaluated using Spearman correlation and multivariable linear regression adjusting for age, sex, and BMI. Results: The mean bag weight was 3.26 ± 0.83 kg and mean SPADI total score was 27.33 ± 20.97. Bag weight demonstrated a moderate positive correlation with SPADI score (ρ=0.524, p<0.001). In adjusted regression analysis, each 1 kg increase in bag weight was associated with a 6.12-point increase in SPADI score (95% CI 3.90–8.34, p<0.001). Male students carried heavier bags and exhibited higher SPADI scores than females (p=0.011). Conclusion: Higher bag weight is independently associated with increased shoulder pain and disability among medical college students, underscoring the need for ergonomic load management strategies in academic settings.