SUNDAY, Aug. 17 (HealthDay News) -- The start of a new school year means it's time to remind students and parents about proper selection and use of backpacks.

"When used correctly, backpacks are the most efficient way to carry a load and distribute the weight among some of the body's strongest muscles," Eric Wall, director of the orthopedic surgery division at Cincinnati Children's Hospital Medical Center, said in a center news release.

However, improper use of backpacks can cause injuries that require medical treatment. For example, backpack-related injuries send almost 6,000 students to emergency departments each year, according to a U.S. Consumer Product Safety Commission report released in 2002.

Wall and his colleagues in the division of orthopedic surgery offer guidelines to prevent school backpack-related injuries:

• When shopping for a backpack, select one that's lightweight, has two wide and padded shoulder straps, a cushioned back, and waist straps. A pack with wheels may be a good option if your child has to lug a very heavy load.
• Children should always use both shoulder straps, and the straps should be cinched tight.
• Limit backpack loads to no more than 15 percent to 20 percent of a child's body weight.
• The heaviest items should be packed closest to the center of a child's back.
• Children shouldn't carry all of their books throughout the school day. They should keep their books in their locker and get them when they need them.
• When wearing or lifting a heavy backpack, children should bend using both knees.
• Don't leave backpacks on the floor where people can trip on them, and don't swing a packs around where it can hit other people.
• If your child uses a backpack and complains of persistent back pain, consult with a pediatrician.

More information

The Nemours Foundation has more about backpack safety.