Bicycle helmets may be harder to fit than you think

Check the bike helmet's condition, slip it over the child's head and tug the straps to make it snug. How hard can that be?

So hard that only 4 percent of people can do it right, according to one study, which warned that improper fit raises the risk of injury in an accident.

"It's deceptively difficult," said researcher Gregory W. Parkinson.

Parkinson, a pediatrician in Falmouth, Mass., checked the helmet fit on 479 patients and their siblings, ages 4 to 18, by having them bring in the helmets when they arrived for regular checkups. After each put on the helmet, Parkinson and a colleague rated its condition and its fit, using a 14-point checklist.

If the helmet did not fit properly, the young people or their parents were given a chance to adjust it.

Surprising numbers

Only 4 percent of the helmets were in good shape and fit right, said the study in the August edition of the journal Pediatrics. Most of the problems were in fit, with many fitting poorly in several categories.

Helmets were too high on the forehead in 52 percent of cases. There was too much front-to-back play in 52 percent. And 33 percent had straps too loose, the examinations found.

"The overwhelming majority of children, adolescents and their parents cannot properly fit a bicycle helmet," the study said.

"The point is that, for whatever reason, it's difficult and it's a skill that needs to be taught," Parkinson said.

Parkinson suggests a three-stage fitting process that he terms "MVP." The "M" is for moving the helmet down to less than two finger widths above the brow, so the helmet can protect the forehead in a crash. The "V" is for the positions of the two side straps, which should be snug in a V shape on both sides of each ear. The "P" is for pulling the strap under the chin snug.

Other experts think the study set too strict a standard for passing, but they agree that most people can't adjust a helmet properly.

The adjustment period

About 20 percent could have passed if Parkinson had accepted helmets that were stable front to back and side to side, said Randy Swart, director of the Bicycle Helmet Safety Institute, an advocacy group in Arlington, Va.

"That to me is the rock-bottom estimate for those who are getting it right," said Swart, who was not connected to the Pediatrics study.

What the study found was "abysmal," Swart said.

"I see appalling fit problems every time I go riding," he said. "I've seen people with helmets on backward. I mean, how bad is that?"

But all the blame can't be put on the users; manufacturers should come up with a system that users can adjust easily, Swart said.

Making a helmet that's comfortable to wear and also easy to adjust is a tough engineering problem, said Thom Parks, vice president for corporate affairs at helmet company Bell Sports in Santa Cruz, Calif.

"It seems so easy, and no one in the world has done it," Parks said. "Europe hasn't figured it out, and Australia and Japan."

It is possible to make a bike helmet that is easy to fit, but it must be a one-piece that covers pretty much the entire head, like a motorcycle helmet -- and most bikers find it uncomfortable, Parks said. The helmets sell among dirt track racers, but otherwise "people stay away from them in droves," he said.

Parkinson's study noted previous research that improper helmet use could raise the risk of head injury by a factor of three.

However, an author of that study said even an ill-fitting helmet is better than no helmet at all.

"When we looked at people who had helmets on, period -- whether they fit or not -- helmets were incredibly effective in decreasing the risk of injury," said Dr. Frederick Rivara, a professor of pediatrics at the University of Washington.