Fitness tips from the physical therapist

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Benefits and Dangers of Backpacks

In the hierarchy of bags, a backpack is a better way to carry life’s necessities than a briefcase or shoulder bag, especially for longer periods of time. Properly worn, a backpack is supported by the strongest muscles in the body: the back and abdominal muscles which work together to stabilize the trunk and hold our body in proper postural alignment. “Typically our proximal muscles, or muscles closer to the trunk of the body, are much stronger and have greater endurance than the distal muscles, those muscles farther away from the center of the body,” University of North Carolina-Chapel Hill's Associate Professor of Physical Therapy Phil Witt, PT, PhD said.

“But improper backpack use can also present some real dangers,” Witt added. Here are some rules of thumb to follow:

Wear both straps. Slinging a backpack over one shoulder causes a person to lean to one side to compensate for the uneven weight, curving the spine. Over time, this can cause lower and upper back pain, strained shoulders and neck, and even functional scoliosis, or curvature of the spine. Teenage girls are especially susceptible to scoliosis. Older adults need to be weary of osteoporosis.

Make sure the backpack is not too heavy. “A backpack can range anywhere from 20 to 50 pounds - more added weight than the average pregnant woman may have to carry,” Witt stated. Even when worn properly with both straps, leaning forward to compensate for this extra weight can affect the natural curve in the lumbar, or lower back, region. Extra weight may cause a rounding of the shoulders and an increased curve in the thoracic, or upper back, region. As a result, the person may experience back, shoulder and neck pain. “A good rule to follow is to carry no more than 15 to 20 percent of one’s body weight,” Witt said.

Pay attention to the type of backpack. Look for backpacks with wide straps. “Narrow straps dig painfully into shoulders,” Witt said, “and our nerves are very close to the surface in our clavicle, or collarbone, region.” Narrow straps can also hinder circulation, causing numbness or tingling in the arms, which over time may cause weakness in the hands. Also look for a backpack with a waist belt. Tightening the belt helps distribute the weight of the backpack more evenly. Even though the latest backpacks with one strap that runs across the body may be fashionable, they are not as functional because one shoulder continually bears the entire weight of the bag. It is also wise to consider the weight of the backpack when empty. For example, a canvas backpack will be lighter weight than leather.

Source: American Physical Therapy Association, www.apta.org