Schoolbag weight carriage in Portuguese children and adolescents: a cross-sectional study comparing possible influencing factors

Abstract

Background Schoolbags and the consequences of carrying them, particularly those associated with overload, are often studied as a health concern. Modifications in gait and posture were reported when children carried loads that corresponded to more than 10% of their body weight (BW). The aims of this study were to verify the load that is carried by Portuguese students and how it is influenced by factors such as school grade, school schedule, lunch site, physical education, sex and body mass index (BMI). Acquiring a more specific knowledge of the Portuguese context and understanding the influence of these factors may allow us to generate proposals to control them in ways that benefit students. Methods The load carried by students in the 5th grade (10.6 ± 0.4 years) and 9th grade (14.7 ± 0.6 years) were weighed with a luggage scale on all days of the week, resulting in 680 evaluations. Data related to the school day were also collected, such as the student’s lunch site, how he or she got to school and his or her school schedule for that day. Individual height and weight were also assessed. Results The 5th grade students carried greater loads than the 9th grade students, resulting in a substantial difference relative to their BW. The school loads of the 5th grade students were mostly greater than 10% of their BWs. Girls tended to carry heavier loads than boys, and overweight students also tended to carry heavier loads. Students who could eat lunch at home carried less weight, and on physical education days, the total load carried increased, but the backpacks of the 5th grade students were lighter. Conclusions The results of the current study describe excessive schoolbag weight among Portuguese students and expound on some of the factors that influence it, which can help researchers and professionals design a solution to decrease children’s schoolbag loads.

Effects of Backpacks on Ground Reaction Forces in Children of Different Ages When Walking, Running, and Jumping

“…However, this limit is often exceeded [30,32]. For example, a recent study found that approximately two-thirds of the Portuguese children analysed, 10 and 15 years of age, carried loads greater than 15% of their body weight at least once a week [29]. Similar results were found by Brzek and colleagues [35] in children from 7 to 9 years old in Poland.…”

“…Mechanical forces influence vertebral growth [26], and high loading rates may have negative effects on bone health [27,28]. In this sense, growing children who use backpacks daily may be at risk, especially if they carry an excessive load, which is the norm [29][30][31].…”

“…This becomes even more disturbing when we realize that younger children carry more weight (normalized to BW) than the older ones. Studies showed that 10-year-old students carried more weight than the 15-year-old students [29], or that students from grades 5 to 8 (ages 8-13) carried more relative weight than those from grades 9 to 12 (ages [13][14][15][16][17][18] [34]. These loads used by young children, at least until 9 years old, can increase the risk of modifications of posture [35], potentially risking later back pain and/or other health-related issues.…”

“…Although the scientific literature on this subject is increasing, investigations should be deepened to further understand the effects of improper use of the backpack. In this way, it has already been suggested that research must understand the influence of the loads carried by children of different ages on GRF and all body movement [29].…”

“…To improve our knowledge on this issue, we thought it important to better understand the effects of using real loads. Therefore, we previously measured the loads carried by the students for a whole week [29] and characterized the backpack weight used by those children that attended the fifth (10 years old) and the ninth grades (15 years old). Backpack load is not the same across the school years [29,35], and children's physical features also become different as they grow.…”