INFLUENCE OF BACKPACK LOAD ON POSTURE AND GAIT BIOMECHANICS IN SCHOOL-AGED CHILDREN
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Abstract
Background: School-aged children frequently carry backpacks that exceed safe weight limits, placing them at risk of postural deviations and altered gait mechanics. International guidelines recommend that backpacks should not exceed 10–15% of a child's body weight, yet students in Pakistan, particularly in urban areas like Lahore, often carry loads beyond this range. This can lead to forward trunk inclination, spinal misalignment, shoulder asymmetry, and compromised gait, ultimately affecting musculoskeletal development and physical wellbeing.
Objective: To evaluate the impact of varying backpack weights on postural alignment and gait biomechanics in school-going children using the Posture and Postural Ability Scale (PPAS).
Methods: A cross-sectional study was conducted from August 2024 to January 2025 across five public and private schools in Lahore. A total of 200 children aged 8–14 years were selected using stratified random sampling. Participants were divided into three groups based on backpack weight as a percentage of body weight: Light Load (<10%), Moderate Load (10–15%), and Heavy Load (>15%). Postural assessments were performed using the PPAS, which scores from 1 (normal) to 7 (severe deviation). Gait parameters, including stride length (cm), walking speed (m/s), and step frequency (steps/min), were recorded. Data were analyzed using SPSS v25, with significance set at p < 0.05.
Results: Students in the Heavy Load group demonstrated significantly higher forward trunk lean (5.2 ± 1.1), shoulder asymmetry (6.1 ± 1.4), and postural instability (5.6 ± 1.3) compared to the Light Load group (1.8 ± 0.9, 2.1 ± 0.7, and 1.9 ± 0.8, respectively; p = 0.000). Stride length decreased from 55.3 ± 4.2 cm to 45.8 ± 6.0 cm, walking speed reduced from 1.2 ± 0.2 m/s to 0.8 ± 0.1 m/s, and step frequency dropped from 110 ± 5 to 98 ± 6 steps/min in Heavy Load group (p = 0.000).
Conclusion: Excessive backpack weight significantly affects postural control and gait biomechanics in children, increasing the risk of long-term musculoskeletal complications. The PPAS proved effective in detecting postural deviations. School-based interventions and ergonomic guidelines are critical to mitigate these risks.
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