For a 150-pound teenager, the recommendation increases to 23 pounds. For a 200-pound adult, it's 40 pounds. Carry the backpack with both straps, keeping them tight, and practice good posture to ...

He says a child's backpack should never be more than 20 percent of their weight. If your kid is 50 pounds, that means their backpack should be 10 pounds or lighter. “If you notice that your kid ...