Children risk long-term back and spinal problems because of poorly fitting and overloaded school backpacks, experts warn.
Children often choose school bags that feature their favourite cartoon characters or brands over back-friendly versions.
The Australian Physiotherapy Association found that up to 70 per cent of schoolchildren were at risk while walking or riding to school with backpacks that did not fit, or were too heavy, health news reported.
The association claimed bad backpacks contributed to back, neck and shoulder pain in students; muscle strain and joint injuries, as well as making children tired.
APA Queensland chairwoman Nicole Haynes said pain and fatigue were the biggest complaints in schoolchildren that could be associated with backpacks.
"More than 50 per cent complain of pain associated with wearing a backpack and 60 per cent complain of fatigue," she said.
Other problems heavy backpacks cause are lower back pain that can last into adulthood and posture issues.
There have also been reports of children with hand and face injuries after tripping over or being hit by their bulging bags.
Ms Haynes said back pain was usually caused by several factors, which made it difficult to only blame the backpacks.
She said she had seen children as young as five in her clinic with back pain and her treatment included looking at their backpack.
"It's hard to get those back packs that fit really little kids," she said.
One Year 3 boy, who weighed just 22kg, was found to be carrying a school bag that weighed 3.25kg.
This was well above the 10 per cent of a child's weight recommendation.
That was on a day when he also had to lug his swimming and library bags.
The problems faced by mums and dads, though, was getting their children to agree to a back-friendly bag and then getting them to wear it correctly.
"The best backpacks are very plain and usually navy blue and maroon," Ms Haynes said.