
Ideally, the bottom of the backpack should align with the curve of the lower back, and not more than four inches below the waistline. A backpack's shoulder-strap anchor points should also rest 1 to 2 inches below the top of the shoulders. (See our backpack Ratings, which are available to subscribers, for models that performed well.)
Things to look for on the inside and outside of a backpack before you buy it include:
Features to look for include wide, padded, contoured shoulder straps that distribute the pack's load over a large area of the shoulder, an abdominal strap, which can help distribute the pack's weight evenly on the back, waist, and hips, and reflectors or reflective fabrics on the pack to add visibility when kids travel to and from school at dusk or dawn.
To prevent discomfort and injury, load and wear the backpack correctly. The American Occupational Therapy Association recommends carrying no more than 15 percent of your body weight in a backpack. But the less you carry, the better for your back.