乌鸦传媒視頻

To protect kids' noggins before setting them on toboggans, parents should ditch ski helmets for hockey or cycling ones, results of a study suggest.

In a small study comparing the three types of head protection, ice hockey helmets provided better protection at lower-velocity impacts, while bicycle helmets were better guards during high-speed crashes, Michael Vassilyadi, MD, of Pediatric Neurosurgery Children's Hospital in Ottawa, and colleagues reported in the Journal of Neurosurgery Pediatrics.

Vassilyadi cautioned, however, that the study does not name one helmet as the best in terms protection because there was no obvious "winner" across categories of crash scenarios.

"The bottom line is that all helmets are protective, and young children should be wearing helmets during winter activities," he said in a statement.

Unlike ice hockey, cycling, and skiing, there's no certified helmet for kids' winter recreation, designed to withstand the specific characteristics of injuries that result from sports like skating or sledding.

Thus, parents use what is available, the researchers said. Still, every year the snowy season brings an uptick in emergency department visits from youths with head injuries.

So to assess which type of helmet, if any, would confer the best protection during these winter activities, Vassilyadi and colleagues compared three types of helmets:

• Ice hockey (777 g, vinyl nitrile)
• Alpine ski (405 g, expanded polystyrene)
• Bicycle (372 g, expanded polystyrene)

The helmets were tested for impacted at various velocities (2, 4, 6, and 8 meters per second [m/s]) via a monorail drop tower that simulated a child falling from a sled.

The aim was to see which helmet diminished acceleration on the head the most; head motion was measured using accelerometers.

The researchers also tested two impact sites on each helmet at the front and on the sides.

For frontal collisions, the researchers found that the ice hockey helmet afforded significantly better protection than the other two during the 2 m/s and 4 m/s impacts for both linear and angular acceleration.

The bike helmet was significantly better than the hockey one during the high-impact condition (8 m/s).

For the side impact, the hockey helmet again outperformed the others during the low-velocity impact, particularly for linear acceleration, the researchers found.

But the alpine helmet beat out the other two for linear acceleration at an 8 m/s crash, and bested the hockey helmet for angular acceleration at that speed as well.

However, the bike helmet was on par with the ski helmet for this latter category, the researchers found.

They warned that a visual inspection revealed cracking and inner liner damage at impacts of 4 m/s, and faster crashes led to large cracks and a "complete breakdown of the energy-absorbing liners" for all the helmets.

Overall, they concluded that hockey helmets did better during lower-speed impacts, while bike helmets outshone the others at higher speeds.

That makes sense, they said, because hockey helmets are designed for numerous clashes in a lower-energy environment, while bike helmets target a single impact during higher speeds.

Still, they said they were surprised at the poor results for ski helmets, as these are supposed to be suitable for an "environment in which there is a high risk for falling as well as the possibility of sliding into objects on the hill."

"This speaks to the need and opportunity for winter play helmets to provide both low-velocity and high-velocity impact protection," they wrote.

The study was limited by its use of an anthropometric dummy to represent the head and neck of a child, and because it only tested a single model of each helmet.