Atlanta, Georgia (CNN)-- By the second week of fifth grade, my son Christopher\'s backpack was already weighing 27 pounds. I know because we put it on the bathroom scale. A thick binder, two textbooks, a novel and miscellaneous supplies are 10-year- An old man weighing only 77 pounds Christopher has no back pain. - Maybe because he had a rolling bag. - But people of his age are not lucky. The Consumer Product Safety Board reported that 7,300 people were injured in the United States. S. Because of the backpack, the emergency room on 2006. The most common complaints are sprain and strain. \"We have seen quite a few children in the school year with back pain,\" says Robert Bruce, a pediatrician at Emory medical school . \". Many people attribute back pain to heavy schoolbags. \"The American Occupational Therapy Association recommends that children weigh no more than 15%. In other words 100- Children weighing more than 15 pounds should not wear backpacks. \"I put the backpack issue in the category\" excessive use damage, \"Bruce explained . \". \"You have a child who is doing something that is over-used, over-stressed, or over-stressed. \"While not all children will complain about the pain, some signs of injury include pain, tingling or numbness when wearing a backpack, red marks, and struggle while wearing or taking off the bag. It is estimated that 40 million American children carry schoolbags. Bruce believes that the number of injuries reported is \"just the tip of the iceberg \". \"Many children are seen in the pediatrician\'s office or are not treated at all. Bruce advised his patients to wear suitable backpacks and ergonomics. His advice usually starts with buying the right bag. \"I think it\'s a great idea for a child with a lighter or smaller size to roll a bag,\" he said . \". But not all schools allow it, he noted. The occupational therapist group recommends buying a bag that is suitable for the size of the child and ensuring good health Shoulder strap padding. \"Of course, the wider straps are safer to spread the strength across the shoulders in larger areas,\" Bruce said . \". The belt also helps to distribute the weight of the bag. The therapist said the bottom of the bag should not be more than 4 inch lower than the child\'s waist circumference. Try loading the heaviest items closest to the child\'s back and arrange the materials so they don\'t slide around. Bruce told some of his patients to ask for a second set of textbooks so they don\'t need to carry them between school and family. Another solution, Bruce suggested, is to ask the teacher if the student can go to the locker more frequently to avoid carrying books all day with him. Bruce gave the last simple suggestion: \"Check your backpack regularly. They are usually filled with unnecessary items. . . . I think if you flip the backpack, you can lose 10 lbs like this. \"It\'s too early for my son to accumulate so much extra garbage during the school year, but, I did follow the expert\'s advice and splurge on rolling packs. At the end of the day at school, I was also helping him carry it into the car. I was wondering if there were statistics showing that parents had a back injury when lifting these bulky bags? E- Judy Fortin is a reporter for CNN Medical News.