The relationship between neck angles and ground reaction forces in schoolchildren during backpack carriage

Abstract

SummaryStudy aim: This study aimed to examine the effect of carrying backpacks on neck posture and ground reaction forces (GRFs) and to investigate the relationship between neck angles and GRFs during backpack carriage in schoolchildren.Material and methods: The craniohorizontal angle (CHA), craniovertebral angle (CVA), sagittal shoulder posture (SSP) and GRFs were measured in right-handed schoolchildren (14 male and 12 female) with mean age 10.17 ± 1.15 years during loaded and unloading conditions. The Qualisys motion analysis system with a force plate was used to assess the neck angles and GRFs.Results: During backpack carriage there was a significant increase in the CHA (p = 0.001), significant decrease in the CVA and SSP (p = 0.001, 0.016 respectively), no significant difference in the normalized (scaled to body weight) vertical GRFs (p > 0.05), and a significant increase in the anterior braking and posterior propulsive GRFs (p = 0.035, 0.002 respectively) compared to the unloading condition. While carrying a backpack there was a moderate negative correlation between the SSP and first vertical GRF (r = –0.464) and a strong negative correlation with the second vertical GRF (r = –0.571) and the posterior propulsive GRF (r = –0.587).Conclusion: Carrying a backpack weighing 15% of the child’s body weight changes the head posture and increases the normalized value of the anterior-posterior shear force. During backpack carriage, decreasing the SSP is associated with increasing the load acceptance, thrusting and posterior propulsive forces. Increasing the shearing force may lead to development of postural abnormities. Consequently, the ideal backpack weight should be considered by parents and teachers.

Biomechanical comparison of sagittal vertebral column bend change induced by backpacks in school-aged children and adolescents: Systematic review and network meta-analysis

“…The review mirrors this trend, though with certain distinctions. Backpacks undeniably cause a reduction in the CV angle, leading to cervical deformation and enhanced shear forces, potentially resulting in abnormal postures like forward head posture [51]. This review also encompasses indices related to cervical spine deformity and demonstrates a similar trend.…”

Podiatric and Stabilographic Examinations of the Effects of School Bag Carrying in Children Aged 11 to 15 Years

“…These scholars found that carrying a backpack weighing 15% of the child's body weight changes the position of the head and increases the normalized value of the anterior-posterior shear force. Increasing this force may lead to the development of postural disorders and defects [25]. In addition to heavy books and notebooks, students carry different personal items in their backpacks that increase the backpack's weight.…”

Ergonomic School Bags: Can Additional Straps Make a Difference in Posture?

“…These bags were used by the students on a daily basis to carry their books to school for a duration of 5 months. For assessing neck, shoulder, and upper back posture, the most commonly used evaluation metrics include the craniovertebral angle, craniohorizontal alignment, and sagittal shoulder positioning (15) . During this time frame, measurements for the CVA, CHA, and SSP assessments were recorded both before and after the period.…”