Modular and Customizable Schoolbag Carrying System for Primary School Students: Optimization and Validation Based on Pressure Distribution Experiments

Primary school students aged 7–12 are in a critical stage of spinal and musculoskeletal development, yet most commercially available schoolbags still adopt standardized sizes that cannot adequately accommodate children’s substantial body-type differences. This mismatch often leads to concentrated pressure on the shoulders and waist, increasing the risk of discomfort and long-term postural problems. To address this issue, this study proposes a modular and customizable schoolbag carrying system for primary school students based on pressure distribution experiments. First, anthropometric measurements were conducted to identify key body-type characteristics related to schoolbag fit. Then, the carrying system was decomposed into three core support modules, including back, waist, and shoulder components, and their dimensional parameters were optimized through pressure distribution testing. Based on the experimental results, a body-type-to-module mapping strategy was established. Finally, a modular prototype was developed and compared with a conventional schoolbag under static standing and dynamic walking conditions. The results showed that the proposed system improved pressure distribution, reduced local high-pressure concentration on the shoulders and waist, and enhanced fit for children with different body types. The study demonstrates that integrating anthropometric stratification, pressure-based optimization, and modular design can provide an effective approach for developing ergonomic schoolbags with both personalization and mass-production potential.