“Unfortunately for some students, back-to-school month means a high risk of back injury,” says Dr. Lisa Muller Muñoz of Bernards Chiropractic in Basking Ridge. Many children complain of back pain after cramming too much stuff into their backpacks. Muñoz advises kids to lighten their load. The New Jersey Association of Chiropractors supports the Backpack Safety America program and recommends that a loaded backpack should weigh no more than 15 percent of the wearer’s body weight, particularly with small children. Another helpful tip: Students should pack heaviest objects first so that they are carried lower and closer to the body.