EFFECTS OF BACKPACK LOAD AND WEARING PREFERENCE ON SPINAL POSTURE IN ELEMENTARY SCHOOL STUDENTS

PURPOSE: Few studies have been done to determine if the method of wearing and the load contained within a backpack can contribute to axial skeleton dysfunction. This study was designed to see if a relationship exists between the weight of the backpack, the way it is worn by the student, and cervical and thoracic spine deviations in the frontal and sagittal planes. SUBJECTS: Fifty-seven fifth graders who carry backpacks ([bar]X=10.8, SD=0.6 years). METHODS AND MATERIALS: Cervical and thoracic deviations were measured with a bubble inclinometer mounted on a headpiece and three plumb lines. Measurements were taken with and without their backpack and after they walked a 190-foot circuit. ANALYSES: The students were divided into three groups according to their backpack weight as a percentage of their bodyweight ([is less than] 10%, 10-15%, [is greater than] 15%). Statistical analyses involved calculation of means, standard deviations, one,way ANOVAs, and an independent t-test that compared one-strap carriers from groups 1 and 2 for cervical lateral flexion. RESULTS: Significant deviations were observed between the lightest ([bar]X=8.72%, SD=2.41) and heaviest ([bar]X= 18.10%, SD=3.73) backpacks for cervical lateral flexion for two-strap carriers (group 1, [bar]X=1.57, SD=0.98, group 3, [bar]X=5.60, SD=5.03, p=.02), and forward head (group 1, [bar]X=3.03, SD=1.91 and group 3, [bar]X=5.21, SD=2.15, p=.004). A dose dependent increase in forward head and thoracic spine flexion (group 1 [bar]X=1.67, SD=2.22, group 2 [bar]X=3.02, SD=1.51, group 3 [bar]X=3.78, SD=2.24) in relation to backpack weight was observed. No significant differences were observed between the light and heavy backpacks for thoracic flexion deviation; however the means show that the greatest increase in thoracic flexion occurred between the light and medium weight backpacks with a mean difference of 1.37 (critical value 1.38). CONCLUSION: We demonstrated a positive linear correlation between backpack weight and spinal deviations in the cervical and thoracic spine (sagittal plane). Wearing preference of one strap resulted in increased neck side bending in subjects at lower weights. With the goals of minimizing spinal deviation, the authors recommend a maximum weight no greater than 10% of the students body weight due to the deviations in spinal posture observed in this study.
Lohman III E, Wong M, Blood J, Detwiler K, Foote A, Israni V, Merchan W, Pasamonte L. School of Allied Health Professions, Loma Linda University, Loma Linda, [...]