The weight of pupils' schoolbags in early school age and its influence on body posture.
Postural development progresses through a series of stages (growth spurts, development of balance and coordination, postural stability) which occur when children are at school age. The reduction in the level of physical activity, increased body weight, overloaded school bags, asymmetry of the backpack straps, the method of putting on and taking off the backpacks and increased usage of electronic devices have negative side effects such as bad body posture habits.



A prospective cohort study in the group of 155 pupils at early school age 7-9 years old has been conducted. Examinations have been conducted twice: first, at the beginning of the school year (initial examination) and second - after 10-11 months (final examination). Age, gender, BMI, weight of school bag carried to school and the length of straps have been assessed. Body posture measurement (using Adams' test), the evaluation of the plumb line deflection from the gluteal cleft, the angle values of kyphosis and lordosis (according to Dobosiewicz methodology) and the pelvis and shoulder blades position (using a ruler and pediscoliometer) have been also measured.



The mean weight of a school bag in the initial study was 6.3 ± 0.8 (range between 4,7 and 9 kg). A tendency to carry slightly heavier school bags was noted in boys (6.7 vs. 5.9 kg; p = 0,00001). This tendency has linearly changed with age (R = 0.68; p < 0,001). In 3.2% of all school bags of children, weights exceeded norms with regard to the weight of the pupil. The increase of torso rotation exceeding norms was observed in 35.3% of girls (mean 2.7 ± 1.2) and in 60.9% of boys (mean 2.3 ± 1.3). The increase of kyphosis angle was noted in 48.5% of girls and in 36.8% of boys. The difference of straps length had a significant influence on the increase of rotation in upper thoracic spine, thoracolumbar junction and it also had influence on the decrease of lumbar lordosis in the group of girls.



Differences in the weight of school bags after one school year have influenced changes in body posture abnormalities, especially in rotation parameters. Backpack straps asymmetry was noticeably stronger in the group of girls and the difference between braces may have an impact on some posturometric parameters. Lack of proper backpack lifting skills tends to create programs and training systems in this regard.
Department of Kinesiology, School of Health Sciences, Medical University of Silesia, Ul. Medyków 12, 40-754, Katowice, Poland. aniabrzek@interia.pl.
Anna
A
Brzęk
Lectureship Prevention, Health Promotion, Department of Biology and Environmental Sciences, Carl von Ossietzky University, Oldenburg, Germany.
Tarja
T
Dworrak
Lectureship Prevention, Health Promotion, University Witten/Herdecke, Faculty of Health, School of Medicine, Hagen, Germany.
Markus
M
Strauss
Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, USA.|Department of Physiology, Faculty of Medicine, University of Valencia and Fundación Investigación Hospital Clínico Universitario de Valencia, Instituto de Investigación INCLIVA, Valencia, Spain.
Fabian
F
Sanchis-Gomar
Faculty of Public Health, Lebanese University, Saida, Lebanon.
Ibtissam
I
Sabbah
Lectureship Prevention, Health Promotion, University Witten/Herdecke, Faculty of Health, School of Medicine, Hagen, Germany.
Birgit
B
Dworrak
Lectureship Prevention, Health Promotion, University Witten/Herdecke, Faculty of Health, School of Medicine, Hagen, Germany.
Roman
R
Leischik
D000367:Age Factors; D001696:Biomechanical Phenomena; D015992:Body Mass Index; D002648:Child; D002657:Child Development; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology; D017770:Lifting; D008141:Lordosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D011187:Posture; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D013131:Spine / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016474:Weight-Bearing
Asymmetry; Body posture; Pupils; Weight of the school bag