Springfield mother Patty Maton knew something was out of whack when she sent her daughter Veronica off to fifth grade two years ago. Veronica weighed 70 pounds. Her backpack weighed half as much.

The result was that Veronica listed this way and that, her back hunching over like St. Louis's Gateway Arch.

"Sometimes when you'd go to stand up, you'd fall backwards," said Veronica, now 12 years old and a seventh-grader at Lake Braddock Secondary School in Burke.

Her mother voiced her concerns to Veronica's teacher. "If you're carrying something half your weight, it's just not healthy," said Maton. "The school didn't feel like it was a real big concern. I felt it was."

She's not alone.

Increasingly, pediatricians, physical therapists and other medical professionals say, they are seeing more patients, at younger ages, complaining of muscle aches, fatigue, numbness and back pain associated with the ever-expanding size of their backpacks.

"It's a hot topic," said Howard A. King, a spinal deformity surgeon on the clinical faculty at the University of Washington in Seattle. "We're getting a lot of calls from pediatricians and seeing quite a few patients coming in with shoulder and back complaints."

Patrice M. Winter, a physical therapist in Fairfax City, has been in practice about 25 years, specializing in the treatment of chronic, unresolved pain. "We never used to see kids," she said. Now they come in as early as second grade complaining of headaches and stiffness, which Winter attributes to a combination of overloaded backpacks and time spent at the computer.

Stand on any street corner as children wait for the school bus in the morning and the problem quickly reveals itself: small ones teetering under the weight of backpacks that dwarf them, middle schoolers with musical instruments and athletic gear crammed in with their books and binders, high school students going for the "in" look by slinging their heavy packs over one shoulder.

"They really load 'em up," said King, who jokingly refers to school backpacks as "self-contained adolescent life-support systems."

"I've even seen them with skateboards hanging off the back."

While some schools have banned backpacks in classrooms, citing safety and health concerns, others have gone in the opposite direction, removing their lockers and forcing students to carry everything they own with them. Some students do that anyway, by choice.

Emily Gerdelman, a 14-year-old freshman at McLean's Madeira School, proudly boasts that "I keep everything in my backpack. One year I didn't clean it out all year."

When Jessica Walczak started complaining about shoulder and neck pain last year, her mother thought it might be sports-related or anxiety about starting middle school. Instead, doctors blamed her backpack.

"I couldn't sleep at night because of the pain," said Jessica, now 12 and in seventh grade at Williamsburg Middle School in Arlington. "Every time I moved my head, it hurt."

While health care practitioners agree that carrying too much weight can strain young muscles and joints, the degree of risk to healthy children is less certain.

As chairman of the American Academy of Orthopaedic Surgeons' committee on public education, John Sarwark hears from lots of doctors and parents concerned about the loads that children lug to school and back each day.

While not downplaying their concern, Sarwark said that "so far as we know, there is no known serious, long-lasting harmful effect to the spine [from toting a heavy backpack]. It's reasonable to say they can cause muscular fatigue, aching, mild discomfort and soreness. But that's the extent of it."

Mario Turi, a pediatric orthopedist at Children's National Medical Center in Washington, agrees. "I get a lot of questions about whether it will cause deformities of the spine, and I emphatically say, 'No, you will not get scoliosis [curvature of the spine] from carrying a heavy backpack.' "

Doctors do recommend that children with scoliosis not carry backpacks, and instead keep a set of schoolbooks at home.

Turi and others note there have been no long-term scientific studies of backpack problems in healthy children. Even so, "the absence of a study does not mean the absence of truth," said Jerome F. McAndrews, a chiropractor and spokesman for the American Chiropractic Association, which takes the view that "improper use of backpacks can lead to muscle imbalance that could turn into chronic back and neck problems later in life."

With 6 million Americans a year seeing doctors for back problems, "we already have an epidemic of back pain in this country," said McAndrews. "From my profession's point of view, this backpack fad is setting us up for even worse problems 20 or 30 years down the road."

"It's a long-term thing," concurred Winters, the Fairfax physical therapist. "The body is very resilient. It can handle a lot. But if you abuse it over and over again, you have mechanical breakdown. If these kids are already having enough damage that they need care--I mean, kids aren't supposed to hurt--then I think it can have some long-term effects."

A survey of nearly 1,200 youngsters in Grenoble, France, a few years ago found that more than half had problems of the vertebrae. And a 1997 survey of 11- and 12-year-olds by the London-based National Back Pain Association found that 80 percent were wearing their backpacks improperly and that some were hauling around as much as 60 percent of their own weight.

Specialists say that ideally backpacks should weigh no more than 15 percent of a child's weight, and never more than 20 percent. It's a target based more on consensus than medical analysis.

Some countries--among them Brazil, Poland and Egypt--have recommended weight limits for backpacks; in this country, the American Academy of Orthopaedic Surgeons and the American Academy of Pediatrics are collecting data for possible further study. The orthopedists' group expects to release some early research next month.

Arlington parent Laurie Seymour estimates that her older daughter, Julia, a senior at Yorktown High, carries close to 50 pounds in her backpack. "It's ridiculous," said Seymour, who now buys extra copies of some of her two daughters' weightier books so the girls don't have to haul them to school and back. "When I was in college, I never carried such heavy books for that long."

Indeed, textbooks do seem to be getting larger. The upper-level chemistry book used at Madison High School in Vienna has 1,250 pages and weighs five pounds; the calculus text has 1,000 pages and weighs 3 1/2 pounds. Elsewhere, a high school biology text put out by Holt, Rinehart and Winston that weighed three pounds back in 1965 has now doubled in heftiness.

Textbook publishers say the reasons for this include advances in knowledge and added state requirements for what must be taught, as well as the inclusion of more visual images and other teaching tools to help slower learners. "Publishers are being asked to include so much more in a book today in order to meet state standards," said Kathryn Blough, assistant director of the school division of the Association of American Publishers. What's more, states require certain types of paper and heavier binding to make textbooks last longer.

Backpack manufacturers add to the problem by finding new ways to cram more into, and onto, their products. One model advertises itself as having 2,500 cubic inches of space: "Stuff a whole day's supplies into this ultimate backpack," its sales tag reads. Other backpacks come with mesh pockets on the outside for shoes and sports gear, special holders for compact discs and cell phones, elasticized cords across the back for additional capacity, and detachable lunch coolers underneath.

Ergonomists such as Alan Hedge, a professor with Cornell University's College of Human Ecology, say the basic backpack design is fundamentally flawed, requiring its wearer to use 10 percent more energy than if using a saddlebag (with the load apportioned front and rear). "When everything is on the back, it creates a force, a tendency for the back to want to fall backwards. The key is to try and get some balance, where instead of all the weight pulling on the back, some is pulling toward the front as well," he said.

Such innovations have started to make inroads. While dismissed by some students as dorky in appearance, saddlebags and backpacks with slightly curved or molded backs and bottoms, inflatable air bags, handles, wheels or interior rack frames are becoming more visible if not yet fashionable.

Debbie Thomas selected a backpack on wheels for her older son this year. Eleven-year-old Alan, who attends Immanuel Christian School in Springfield, said he's relieved that his shoulders will get a break from the soreness he experienced last year. Even so, he admitted recently, he's a little worried about how he's going to get his new, rolling backpack down the stairs at school.

Jessica Walczak, the Arlington student who sought medical help for her back and neck pain last year, said she felt "kinda weird" lugging around the backpack on wheels that her doctors recommended. "No one else had one, and I couldn't fit it in my locker," she said.

After a few months, she got her school to let her keep some of her heaviest books at home, and back on went her backpack.

"It's definitely still a concern," her mother, Tracy, said last week. "We'll just see how it goes this year."

TIPS ON BACKPACKS

Ideally, backpacks should weigh no more than 15 percent of the wearer's weight. Students should make one or more trips to their school locker each day and carry only what's necessary. If you feel yourself straining forward to walk, lighten the backpack.

Backpacks should have wide, padded shoulder straps. A backpack with several compartments can better distribute the load.

Pack the pack correctly, with heavier items closest to the back. Pointy or bulky objects should not rest against the back.

Wear both straps, and the waist belt if there is one. Slinging a backpack over one shoulder can cause strain and fatigue. Straps should be fastened snugly but not too tightly.

The backpack should hang just below the shoulders and rest on the hips and pelvis.

Use reflective tape on the exterior to increase visibility.

Talk to your child's teachers about staggering which nights the bigger textbooks must be brought home, or limiting homework to lighter handout material. At Cooper Middle School in McLean, students keep their core subject books at home and a separate set in the classroom. Principal Bernard Gross said it not only eases the strain on students' backs, but the books last longer, too.

Sources: American Academy of Pediatrics, American Chiropractic Association, Consumer Reports