The modern school backpack has evolved, but it hasn’t necessarily gotten lighter. Individually, those items may not seem heavy, but together they can add unnecessary strain to children’s bodies. Dr. Sadika Kendi, a physician who chairs the academy’s injury-prevention efforts, says back injuries are uncommon but possible, particularly if a child falls while carrying a heavy backpack. “It’s worse if, for example, they trip and fall and they have a huge, heavy backpack on their back. The American Academy of Pediatrics also recommends teaching children to pick up and carry backpacks safely, including bending at the knees rather than the waist when lifting heavier bags to avoid strain.