At 3 p.m. on Thursday afternoon, the hooked walls in School House A and D at Strawberry Park Elementary School were lined with black, pink, purple and blue medium-sized backpacks.
As students gathered their belongings to head home for the day, coats, gloves, snowsuits, school papers and binders were stuffed into these oversized satchels.
As they ran out the door to greet mom or dad, the large lumps on their backs would tip over if they stood straight in one place for too long.
"(The weight of my backpack) is in the middle. I just like walking like that," said Callie Hvambsal, after her first-grade teacher Jan Acker leaned forward, mimicking Hvambsal's back-packed posture.
Hvambsal, 6, said she carries papers, a snowsuit, stuffed animals, art work and lunch in her backpack.
A study done by the Society for Academic Emergency Medicine in 2000, reported that at an elementary school in Ohio, 23 percent of the children carried a backpack weighing 20 percent of their body weight.
In essence, a 100-pound child could weigh 120 pounds with a backpack, and how many 100-pound elementary school students are there?
Julie Van Buskirk, mother of three Strawberry Park students, said her older boy carries more than the younger ones because of the course load and responsibilities.
"They don't complain, they're boys. My fifth-grader thinks he's stronger than me," Van Buskirk said.
Many may not complain of carrying an average 13.81-pound backpack everyday.
Michael Ressler, physical therapist at Kinetic Energy Physical Therapy, said an older body that is fully developed is equipped to handle more strenuous weight than the average elementary school student's body.
But every child is different and each child carries a different weight.
"Generally, you need to look at a child's strengths and weaknesses, their posture, if they have developmental problems," Ressler said. "It's very individually based."
Ressler said the best backpack scenario is carrying it over the shoulders with a waist strap.
The better scenario is over both shoulders and the good scenario is carrying it in the hand. Carrying a backpack over one shoulder is not healthy for the back.
"The hip and pelvis is the strongest and most stable area of the entire body," Ressler said. "By the hip (or waist) straps, weight is transmitted through shoulders."
Ressler said having a strong trunk area will help extremities function efficiently.
After a bit of research conducted by the Steamboat Pilot, it found that out of 34 elementary school students, the average weight of a backpack was 6.5 pounds. A 95-pound student weighed 115 pounds with the backpack. The lightest backpack was 2 pounds.
As Jessica Dunlop, Whitney Blackburn, Erin Duran and Natalie Geer, all in second grade, circled around and shouted all the things they carried in their backpacks, kneeling on the ground, Casey Green stuffed his with a coat, papers and books.
"It's real heavy. It gets tiring," Green said while slinging his black sack over one shoulder.
Van Buskirk said she's seen some of the new alternative backpacks, the one-strap pack the rests on the hip or the backpack on wheels, but hasn't thought about it for her kids.
"My purse is too heavy. If my purse is heavy, I can't imagine a kid keeping (a backpack) on that long," Van Buskirk said.
Caroline Rogger, seventh-grader at Steamboat Springs Middle School, said every year the weight increases and this year is worse than last.
"It varies a lot. Sometimes you have to bring home your Spanish book, your English book and a binder, sometimes it's just a binder," Rogger said. "It depends on how much homework you have."
With basketball practice uniforms and lunch bags, Rogger said it can get pretty heavy and at the end of the day, she's happy to be alleviating her shoulders from the stress.
Michelle Nesin, physical therapist at Johnson and Johnson said heavier backpacks cause people to lean forward, pushing the pelvis forward and the shoulders back, which leads to poor posture.
"The hips and shoulders should be directly over each other," Nesin said, adding that shifting the pelvis forward and the shoulders back doesn't keep the weight of the backpack centered and creates an arch in the back.
The Consumer Products Safety Commission of 1999 reported that about 4,928 emergency room visits each year result from injuries related to book bags and back carriers. These injuries can lead to long-term problems, as evidenced by a recent scientific experiment which found that carrying a backpack alters the mobility of the spine and leads to restricted movement, a risk factor for back pain.