Watching students carrying their backpacks on a college campus can be a chiropractor’s nightmare, for much damage is in process to young backs that will show up years later in multiple back problems. “A lot of people are wearing their backpacks too heavy, which is harming their backs and their health,” said Allison Gross, a chiropractor at the EnCana Wellness Center at Mount Royal College in Calgary, Alberta.

And Jim Krumpak, a chiropractor in Youngstown, Ohio, said heavy book bags could cause eventual disc injury, bone spurs, thinning of discs and nerve irritation. He said backpacks should be about 15 percent of a person’s body weight.

At Youngstown State University, a survey of 50 students showed that students carry book bags that weigh anywhere from five to 30 pounds. “Heavy book bags can certainly affect young adults. Most studies have focused on high school students, but they can also apply to college students,” Krumpak said.

The biggest backpack sins include carrying the bag on one shoulder, failing to use the waist strap and letting it rest too far down the back, Gross said, suggesting the following tips: On the 15-percent-of-body-weight rule, “closer to 10 percent is better,” she advised. Use a backpack that has shoulder straps that are at least two inches wide and padded. Always use both shoulder straps.

“If your bag is slung over one shoulder, even with a light weight, it’s unhealthy for the spine.” — The top of the backpack should be at shoulder level and the bottom no lower than the top of your hips. Use the waist straps to make sure the backpack fits snugly against your back.