Of all the back-to-school decisions parents in Lawrence make this week, one that could have long-lasting impacts on their child’s health is … which backpack to use.

Local chiropractors say having a sturdy backpack that’s not too heavy and worn properly could save kids from developing back, neck and posture problems. A good guideline for parents to keep in mind is that a backpack should weigh about 10 percent of a child’s body weight.

“I have a lot of parents who will bring their kids in a couple months or so after school starts because they’re complaining of lower-neck pain or mid- or lower-back pain,” said Lawrence chiropractor William Miller. “I advise parents to weigh that backpack. Well, weigh the child, then weigh the backpack.”

Miller says backpacks should weigh no more than 10 percent to 12 percent of a girl’s body weight or 12 percent to 15 percent of a boy’s weight.

“If you have a 100-pound child, you don’t want it to weigh more than 10 to 12 pounds,” he said. “If you don’t think that’s a lot, strap a gallon of milk to your shoulder and wear it around all day.”

Kids with overly heavy backpacks risk disc problems, spinal misalignment, altered posture, even scoliosis.

“When you’re an adolescent and in the growing phase, you’ve got a lot of pressure on bones, joints, discs, ligaments,” Miller added. “You don’t want to be overloading that. It’s just a lot of stress on the growing spine.”

Lawrence chiropractor Christopher Kauffman, who has recently been offering free backpack checks to students, compares a child wearing too heavy of a backpack to an adult who does a repetitive action at work that leads to injury, such as carpel tunnel.

He recommends parents buy a durable backpack, with two padded straps, that isn’t longer than the child’s torso and that has multiple pockets to even out the weight load.

“I don’t know that you have to go out and get the highest dollar backpack that’s there,” Kauffman said. “But a $2 plastic backpack that’s going to end up costing the child injuries and the parents money to correct those injuries isn’t worth it in the long run.”

Other options include backpacks that roll on wheels and wearing hip belts that can help distribute the weight of a backpack.

Lawrence’s Sunflower Outdoor & Bike Shop offers higher-end backpacks for youth, such as the Deuter, Patagonia and North Face brands. Sales associate Chris Cecil that while they are on the pricier side, it’s because they’re better quality and likely to last several years.

Cecil, a self-described backpack nerd, says kids and parents can even take their cues from backpackers like him.

“It’s about how you distribute the weight,” he said. “The heaviest things should be closest to your back and the lightest things further out. That way it’s pulling on you less.”