Have you ever watched children getting off the bus to begin their day at school? If you have, you probably noticed that most of the children were hauling heavy back packs which caused them to twist and turn and lean over in an unusual position as they struggled to their classroom.

It is time for back-to-school shopping and most students have a backpack at the top of their wish list. As an educated parent, it is important to realize that buying a fashionable looking backpack may not be the right choice. Instead it is vital that the backpack purchased is one that fits your child and is designed to promote appropriate posture and prevent injuries.

Before you buy that trendy backpack that your child is begging for, consider appropriate backpack construction. Wearing the wrong backpack may lead to injuries and can harm the muscles and joints in the body. Improper use of a backpack may lead to poor posture and can cause a variety of thoracic and lumbar spinal problems, shoulder strains and neck injuries. The repetitive motion of taking the pack off several times per day also can contribute to injuries.

The Consumer Product Safety Commission estimates that more than 5,000 emergency room visits each year result from injuries related to book bags. A study conducted by the American Academy of Orthopaedic Surgeons revealed that backpack injuries are on the rise. In total, 58 percent of the orthopedists surveyed reported seeing children with related backpack injuries and more than 70 percent of the physicians surveyed indicated that heavy backpacks can become a nation wide clinical problem and lead to future problems. By the end of their teen years, more than 50 percent of youth experience at least one low back pain episode. New research indicates that this increase may be due, in part, to the improper use of backpacks.

Backpack safety

· Purchase a pack that weighs approximately one pound and has wide, adjustable padded shoulder straps. Thin straps can compress the shoulders and cause damage to muscles, nerves and blood vessels. Ideally, the pack should have waist straps which will help distribute some of the weight through the hips and lower body and decrease the stress on the shoulders and spine. The length of the pack should not be more than the length of the child's back and should not be lower than the waist. In addition, backpacks that offer multiple compartments may help students stay organized.

· The maximum weight of the loaded pack should be 15 percent of the carriers body weight. If the weight of the pack causes the wearer to bend forward or backward, it is too heavy. Placing the heavy books closest to the spine will help distribute the weight in a better fashion and keep the weight close to the wearer's center of gravity. In addition, students often need to be taught how to evenly distribute the weight in the pack and prioritize what they pack.

· The pack should be securely fastened and worn so that straps are placed over both shoulders. Wearing the pack on one shoulder is truly the cause of most pack related injuries. Many kids wear their pack over one shoulder because it looks cool, but they end up leaning to one side to offset the extra weight. This can lead to serious spinal injuries. In addition the pack should not hang below the waist and it is imperative to use the waist strap if available. Upright posture that aligns the ears, shoulders and hips must be maintained while standing and walking. When putting the pack on, it is recommended that the student faces the pack, bends the knees, lift the weight of the pack with both legs and both arms and place the straps on the shoulders one at a time. Do not sling the pack onto one shoulder.

· Avoid taking the pack off and on when possible. When getting on the bus, the pack can be taken off after the child is seated and the pack is resting against the seat. When going into the classroom the student may want to back up to the school desk and rest the weight of the pack upon it prior to taking off the pack. Avoid placing the pack on the floor when possible and try to place it on an elevated surface to avoid repetitive bending.

Some parents may choose to purchase a backpack on wheels, this may be a wise purchase in some instances but in others, trying to maneuver a pack on wheels in crowed halls, on and off the bus and on unlevel surfaces may be difficult.

Cindy Merrick is a physical therapist at Therapy In Motion in Norman.