Backpacks are handy tools that carry an array of gear. Students rely on them to hold books, while hikers and campers utilize backpacks to carry items such as food and beverages that keep them safe on trails. Even office workers may turn to backpacks to carry laptops or other tools of the trade.

Backpacks are handy resources, but overstuffed backpacks may cause injury. Backpacks should only carry weight that people can handle, and there are guidelines that can help people safely utilize backpacks.

The weight of a backpack depends on the age of the person using it. Generally speaking, adults should not exceed 20 percent of total body mass when loading backpacks. That means a healthy person weighing 200 pounds should not carry more than 40 pounds in his or her backpack.

In regard to children, researchers indicate that a child’s backpack should weigh no more than 10 percent of what the student weighs. Those findings are based on a Spanish study involving 49 primary school-aged children. Therefore, if a child weighs 70 pounds, he or she should only carry up to 7 pounds in the backpack.

Individuals also should follow a few other backpack recommendations to alleviate injuries. It’s not a good idea to wear a backpack hanging from only one shoulder. A backpack should be worn on both shoulders, and ideally with a lumbar strap. This will help to prevent muscular pains by providing well-rounded support.

A backpack with wide, padded straps can minimize pressure on the shoulders, back and collarbone. Backpacks made of lightweight material will not add much additional weight to what’s being carried. Another tip is for children and adults to pack the heaviest item carried in the backpack closest to the center of the back to minimize strain.

Failure to follow guidelines may result in pain and injuries and have negative effects on balance, which may increase the risk of falls or other injuries.

Whenever possible, individuals may want to use trolley backpacks, which are on wheels. They can be dragged, alleviating the need to carry heavy loads.