If your son or daughter is slouching, you may be tempted to poke them in the back and mutter "stand up straight." It worked for our parents and grandparents, after all. But these days kids may have bigger problems than sloppy posture. What was once referred to as the "debutante slouch" has become a more serious problem for many young children and teens. The culprit? Backpacks.

According to physical therapists at Children's Hospital in Boston, MA backpacks can cause muscle strain, neck and shoulder pain, low back pain and curvature of the spine. The recommended weight load is no more than 15% of the child's total body weight, though 10% would be ideal. Some children are carrying an average of 40 pounds or more daily. Many of them sling the backpacks (which are not designed to carry the weight they have crammed into them) over one shoulder. This increases the danger of spine damange and curvature.

Last week the American Occupational Therapy Association held weigh-ins across the country as part of their National Backpack Weigh-in campaign. Karen Jacobs, a Boston University professor and president of the AOTA, spearheaded the initiative. Jacobs says that many students are carrying around excess weight not just because of increased homework loads but because many have after school activities and working parents hustle them from school to extra-curricular activities without making stops in between. The result may be more harmful than we think.

Dr. Tobin Mehmet, a family practioner with West Emerson Medical Associates and Beth Isreal-Deaconess Hospital in Boston says that some children are having a complete change in body posture, movement, and shape.

"Parents may assume that their child's slouch is simply youthful bad posture, but it may be a warning sign. Many children are manifesting a forward leaning gate that can be mistaken for a trend, but it's actually the result of damage being done to young and vulnerable spines."

Kids have also come to covet the backpacks as badges of honor. At many of the AOTA weigh-ins the heaviness of the backpack was seen by kids as a sort of cool status symbol. Dr. Mehmet supposes that perhaps they are showing signs of the culture in which they are reared. "I think many young people consider how busy they are to be something of a status symbol. The more they are doing the more successful they view themselves. The bigger and heavier their backpacks are, the cooler they are."

Whether the forward slouching, backpack toting generation is making a statement about personal style or not, parents need to be aware of possible risks. The Backpack Safety site (http://www.backpacksafe.com/) has some valuable information available to anyone with an internet connection. School nurses should have information available as well.

Some tips recommended by the AOTA:

*Empty your child's pack and discuss what is unnecessary.
*Put the heaviest items closest to your back, lightest items on top of these.
*Consider carrying a second bag to redistribute weight.
*Consider leaving items in the car that will transport the child from school to any activities.
*If your child's school doesn't provide lockers, ask if teachers can provide space in their classrooms for storage during the day.

If the issue seems to be a trivial one, consider this: more than 7,000 emergency room visits in the year 2001 were as a result of injuries from backpacks and book bags and half of those injuries were to children between the ages of 5 and 14. Such numbers are weighty, indeed.