Built Environment and Active Transport (Beats) research has also found about a third of them thought their bag was too heavy to walk or bike to school.
However, the Beats research found female and under-weight adolescents, and those living in large urban areas were more likely to have heavier school bags relative to their body weight, compared with their counterparts.
The research found the average school bag weight of the more than 1500 teenagers surveyed was 5.2kg, and 10% of them carried an additional bag with an average weight of 2kg.
The recommended weight limit for a school bag was 5% to 20% of a child’s weight.
"Excessive school bag weight is a significant issue."
She believed strategies to reduce adolescents’ school bag weight should be part of overall efforts to encourage active transport to school.
"Reducing the amount of school books that adolescents carry to school on a daily basis would be one way to help this.
"It would also help looking at what else they really need to bring to school daily, and if some of it, such as some sports gear, could be stored at school."
She said it was a common misconception that the move to electronic devices had reduced school bag weights.
"More than 85% of adolescents carried books to school and 60% carried an electronic device.
"Adolescents who brought their electronic device to school also had heavier school bags and more frequently reported fatigue and/or pain symptoms from carrying their school bag throughout the day.
"Future health promotion initiatives should focus on designing strategies to reduce excessive school bag weights, particularly for females and urban adolescents," she said.
