Medical experts say children should carry backpacks that weigh no more than 10 to 20 percent of their body weight to avoid lower back pain and associated problems. The range in the recommendations reflects different degrees of caution. On the more conservative end are groups like the , which recommends sticking to 10 percent of body weight or less. For a 60-pound child, that means the pack and its contents should weigh 6 pounds at most.
A review of the medical literature on this issue shows inconsistent recommendations on how to avoid episodes of back pain in children who carry backpacks.