Backpacks come in all sizes, colors, fabrics, and shapes and help kids of all ages express their own personal sense of style. And when used properly, they're incredibly handy.

Many packs feature multiple compartments that help students stay organized while they tote their books and papers from home to school and back again. Compared with shoulder bags, messenger bags, or purses, backpacks are better because the strongest muscles in the body — the back and the abdominal muscles — support the weight of the packs.

When worn correctly, the weight in a backpack is evenly distributed across the body, and shoulder and neck injuries are less common than if someone carried a briefcase or purse.

As practical as backpacks are, though, they can strain muscles and joints and may cause back pain if they're too heavy or are used incorrectly. Here's how to help kids find the right backpack.

Problems Backpacks Can Pose

Although many factors can lead to back pain — increased participation in sports or exercise, poor posture while sitting, and long periods of inactivity — some kids have backaches because they're lugging around their entire locker's worth of books, school supplies, and assorted personal items all day long. But most doctors and physical therapists recommend that kids carry no more than 10% to 15% of their body weight in their packs.

To know how heavy backpacks can affect a kid's body, it helps to understand how the back works. The spine is made of 33 bones called vertebrae, and between the vertebrae are discs that act as natural shock absorbers.

When a heavy weight, such as a backpack filled with books, is incorrectly placed on the shoulders, the weight's force can pull a child backward. To compensate, a child may bend forward at the hips or arch the back, which can cause the spine to compress unnaturally. The heavy weight might cause some kids to develop shoulder, neck, and back pain.

Kids who wear their backpacks over just one shoulder — as many do, because they think it looks better or just feels easier — may end up leaning to one side to offset the extra weight. They might develop lower and upper back pain and strain their shoulders and neck.

Improper backpack use can also lead to poor posture. Girls and younger kids may be especially at risk for backpack-related injuries because they're smaller and may carry loads that are heavier in proportion to their body weight.

Also, backpacks with tight, narrow straps that dig into the shoulders can interfere with circulation and nerves. These types of straps can contribute to tingling, numbness, and weakness in the arms and hands.

And bulky or heavy backpacks don't just cause back injuries. Other safety issues to consider:

• Kids who carry large packs often aren't aware of how much space the packs take up and can hit others with their packs when turning around or moving through tight spaces, such as the aisles of the school bus.
• Students are often injured when they trip over large packs or the packs fall on them.
• Carrying a heavy pack changes the way kids walk and increases the risk of falling, particularly on stairs or other places where the backpack puts the student off balance.

Purchasing a Safe Pack

Despite their potential problems, backpacks are an excellent tool for kids when used properly. But before you buy that trendy new backpack your kid or teen has been begging you for, consider the backpack's construction.

The American Academy of Pediatrics (AAP) recommends that parents look for the following when choosing the right backpack:

• a lightweight pack that doesn't add a lot of weight to your child's load (for example, even though leather packs look cool, they weigh more than traditional canvas backpacks)
• two wide, padded shoulder straps; straps that are too narrow can dig into shoulders
• a padded back, which not only provides increased comfort, but also protects kids from being poked by sharp edges on objects (pencils, rulers, notebooks, etc.) inside the pack
• a waist belt, which helps to distribute the weight more evenly across the body
• multiple compartments, which can help distribute the weight more evenly

Although packs on wheels (which look like small, overhead luggage bags) may be good options for students who have to lug around really heavy loads, they're extremely difficult to pull up stairs and to roll through snow. Check with the school before buying a rolling pack; many schools don't allow them because they can pose a tripping hazard in the hallways.

Using Backpacks Wisely

To help kids prevent injury when using a backpack:

• Lighten the load. No matter how well-designed the backpack, doctors and physical therapists recommend that kids carry packs of no more than 10% to 15% of their body weight — but less is always better. If you don't know what that 10% to 15% feels like, use the bathroom scale (for example, the backpack of a child who weighs 80 pounds shouldn't weigh more than 8 to 12 pounds).
• Use and pick up the backpack properly. Make sure kids use both shoulder straps. Bags that are slung over the shoulder or across the chest — or that only have one strap — aren't as effective at distributing the weight as bags with two wide shoulder straps, and therefore may strain muscles. Also tighten the straps enough for the backpack to fit closely to the body. The pack should rest evenly in the middle of the back and not sag down to the buttocks.

What Kids Can Do

A lot of the responsibility for packing lightly — and safely — rests with kids:

• Encourage kids to use their locker or desk frequently throughout the day instead of carrying the entire day's worth of books in the backpack.
• Make sure kids don't tote unnecessary items — laptops, cell phones, and video games can add extra pounds to a pack.
• Encourage kids to bring home only the books needed for homework or studying each night.
• Ask about homework planning. A heavier pack on Fridays might mean that a child is procrastinating on homework until the weekend, making for an unnecessarily heavy backpack.
• Picking up the backpack the right way can also help kids avoid back injuries. As with any heavy weight, they should bend at the knees and grab the pack with both hands when lifting a backpack to the shoulders.
• Use all of the backpack's compartments, putting heavier items, such as textbooks, closest to the center of the back.

Being a Safe Backpack Advocate

Involving other parents and your child's school in solving students' backpack burdens might help to lessen kids' loads. Some ways the school can get involved include:

• allowing students more time in between classes to use lockers
• purchasing paperback books
• implementing school education programs about safe backpack use
• purchasing books on CD-ROM or putting some curriculum on the school's website, when possible

You may need to adjust kids' backpacks and/or reduce how much they carry if they:

• struggle to get the backpack on or off
• have back pain
• lean forward to carry the backpack

If your child has back pain or numbness or weakness in the arms or legs, talk to your doctor or physical therapist.

Reviewed by: Mary L. Gavin, MD
Date reviewed: August 2010