SCHOOL BACKPACK LOADS AND POSTURAL RISK IN LOCAL SCHOOLS: EVIDENCE SYNTHESIS AND FIELD MEASUREMENT DATA

Abstract

Background: Schoolbag overloading is a documented contributor to musculoskeletal disorders in school-aged children globally. Despite widespread international evidence, no systematic field data exist for Uzbekistan. Objective: To synthesize findings from three evidence-based sources (Mackie, 2006; AL-Qato, 2012; Ashraf et al., 2026) and present field measurement data from Tashkent primary schools to characterize the ergonomic risk posed by school backpacks to Grades 1–4 students in Uzbekistan. Data Sources: (1) Field measurements of backpack and student body weight conducted at Tashkent; (2) Mackie (2006), a five-study PhD thesis examining backpack design, adjustment, carriage duration, and weight; (3) AL-Qato (2012), a cross-sectional study of 800 Palestinian students (Grades 3–9); (4) Ashraf et al. (2026), a PROSPERO-registered systematic review of 12 studies (PRISMA 2020). Key Findings: Toshkent field data show that all four grade levels exceed the recommended 10% body weight (BW) threshold: mean ratios ranged from 11.5% (Grade 4) to 13.18% (Grade 1), with individual maxima reaching 18.6%. Mackie (2006) demonstrated that 15% BW loading produces 50% greater shoulder force than 10% BW and that hip-belt non-use increases shoulder force by 40%. AL-Qato (2012) found that 73% of 800 students carried ≥10% BW, with 47.8% reporting shoulder pain and 21.6% reporting low back pain. Ashraf et al. (2026) synthesized evidence showing that 48.66–65% of schoolchildren exhibit postural deviations, that only 1.9% carry bags correctly, and that 79.3% use asymmetric shoulder straps. Conclusions: Convergent evidence from four independent sources establishes that Tashkent primary school students are systematically exposed to backpack-related musculoskeletal risk. National ergonomic standards, educational interventions, and locally adapted backpack design are needed.