Students who carry single-strap schoolbags may be putting themselves at risk for more than just back problems.
Stephen Legg, associate professor at Massey University in New Zealand, and Christian Cruz, ergonomics student at Lulea University of Technology in Sweden, conducted a study about the effects of different styles of backpacks on the human lungs.
It compares the effect of double-strap backpacks on lung function to the effect of the currently popular single-strap versions.
According to the study, there was “clear and statistically significant evidence” of an increase in restriction of breathing capabilities when students used the single-strap backpack.
The study said this restriction happens because backpack harnesses “oppose the expansion of the chest wall during inspiration.”
Students who carry single-strap backpacks may experience a greater restrictive effect on the middle of their body, which results in more pressure on the chest.
Dr. Timothy Honigman, medical chief of staff at the LSU Student Health Center, said when pressure is put on a chest, the muscles that pull bone away from the lungs are restricted.
This interferes with the normal breathing process, only allowing the lungs to inflate partially. This could lead to health problems similar to those caused by asthma, Honigman said.
The problems reported in the study may not be as evident as previously researched back problems caused by backpacks, however.
“I’ve never seen a student come in with breathing problems related to a backpack,” Honigman said.
Honigman said that, should the study prove true, possible effects of the decreased lung function caused by single-strap backpacks could result in problems from exercise intolerance to increased proneness to chest infections. He said the risk posed to smokers could be even greater because it could possibly accelerate damage already being done.
“I think that, no question, the double-strap is best,” Honigman said.
He said double-strap backpacks keep the weight evenly distributed over the carrier’s upper body. They also avoid putting as much pressure on the chest area as the single strap does.
He said it is important for students to carry the minimal amount of weight in their packs.
Katie Louviere, a biological sciences freshman, carries a single-strap backpack and said she usually does not experience any discomfort.
“The only time I do is sometimes when I carry heavier loads,” she said. “It usually doesn’t bother me.”
Louviere said she has never experienced any chest pains or breathing problems caused by her backpack even though she suffers from asthma.
Aaron Mickey, assistant manager of The Backpacker outdoors store, said the single-strap backpacks are sold mostly to students.
“Most of the people who have to use it for an extended time usually go with the double-strap,” he said.”It’s going to be more comfortable.”
Mickey did not have any comment on the pack’s effect on the lungs, but he said that double-strap backpacks are “more comfortable” in most aspects.
The data in the study was gathered using machines to calculate lung volumes, flows, and expirations of the subjects. The measurements were taken without a backpack, with a double-strap backpack, and with a single-strap backpack.