One health expert says thousands of Iowa children are overdoing it when it comes to the books they’re lugging around in their backpacks. Des Moines occupational therapist Janet Lebsack says kids need to learn to “Pack it Light and Wear it Right.” She says the American Occupational Therapy Association finds most students are carrying way too many heavy books on their backs. Lebsack says it’s recommended a child carry no more than 15-percent of his or her bodyweight in the backpack — so a 100-pound kid should carry a backpack no heavier than 15-pounds. She says some kids like to sling the backpack over one arm — and that’s a no-no.Lebsack recommends using both armstraps, one over each shoulder, and a waist belt to more evenly distribute the weight. She says “We’re seeing more children with stooped shoulders, sore necks, and aching backs from carrying school backpacks and we can’t afford to put our children at risk for a lifetime of problems.” She acknowledges some teachers pile on the homework, forcing a student to cram five or six textbooks into their packs per night. Lebsack says there are better ways to haul that all home. She says if you absolutely have to carry more books than that 15-percent, carry the rest in your arms to avoid hurting your spine, or get a bookbag on wheels, if the school allows them. A study finds more than 40-million children in the United States carry backpacks and more than half of them may be carrying too much weight. The U.S. Consumer Product and Safety Commission estimates more than seven-thousand emergency room visits in 2001 resulted from injuries related to backpacks and book bags, and half of those occurred among children between the ages of five and 14.