Photos: The kids & their backpacks
Experts say to avoid back pain, your backpack should not be more than 10 to 20 percent of your body weight. Ellen Warren went to Oak Park's Brooks Middle School to find out just how much poundage the students were carrying. Here's a sample of what she found.
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Ainsley Tran, 12, seventh grade: "Our teachers give us our textbook to keep at home and they keep one in the classroom so we don't have to take the book back and forth." (Percentage of body weight: 20.5 percent.)