Young hockey players who keep their heads up and brace themselves as they anticipate collisions really can reduce the severity of head impacts, as coaches say, a study of boys wearing special helmets has found.
The U.S. Centers for Disease Control and Prevention calls traumatic brain injury a serious public health problem in the U.S., where children under age 15 account for about 40 per cent of the 1.1 million such injuries that send people to hospital emergency rooms each year.
Since young hockey players have previously been shown to suffer head impacts as severe as those of college and university football players, researchers, hockey associations, coaches and parents are looking for ways to reduce such injuries.
In Monday's online issue of the journal Pediatrics, Canadian Jason Mihalik of the Department of Exercise and Sport Science at the University of North Carolina at Chapel Hill and his colleagues reported the severity of head impacts can be reduced in young hockey players who anticipate a collision, particularly for moderate-intensity impacts.
Moderate impacts are serious enough to cause potential injury but don't stand out as dangerous to a coach, parent or players, Mihalik said.
"I think parents need to appreciate that concussions can occur over a wide range of impact — it's not necessarily the more severe impacts that will cause injury. We've seen collisions that we've often dismissed as very trivial as causing concussion in young hockey players," Mihalik said in an interview.
The findings come down in part to what coaches and parents commonly say: Keep your head up when skating and don't stare down at the puck at your stick.
Brace for collision
"You want to be heads-up, you want to see what you're hitting, you want to see that you're about to get hit. But you also want to be in a ready athletic position to absorb the forces of that collision," Mihalik said.
The researchers were able to lend scientific backing for the advice after asking 16 male bantam hockey players, who were an average age of 14, to wear custom approved helmets fitted with six accelerometers. The devices recorded the severity of head impacts and where they occurred: top, side or back of the head.
Over a 54-game season, the study's authors analyzed 666 body collisions that were recorded on video and time-stamped to match the collisions recorded in real time from the helmets on a sideline computer. Of the collisions, 421 occurred along the boards and the remaining 245 were on open ice.
After reviewing the videos and biomechanical data from the helmets, the researchers concluded that anticipated collisions tended to result in less severe head impacts than unanticipated collisions, especially for medium-intensity impacts.
Open-ice hits worse?
The study's authors also found that open-ice collisions resulted in greater linear and rotational accelerations of the head, compared with collisions along the boards. The higher open-ice accelerations were likely the result of the movement of the player's head, the team said. It is thought that rotational strains contributing to traumatic brain injury may be more likely to result in concussions, compared with linear or straight accelerations, the researchers noted in the study.
If a player doesn't anticipate a collision, all of the force is directed through the mass of the head and the resulting accelerations are quite high, Mihalik said.
When a player anticipates a hit, though, he can tense the neck muscles so the same force gets directed at the higher mass of the head, neck and torso, for example, and acceleration of the head itself will be far less, he added.
That's where Mihalik's second piece of coaching advice comes in: be in a ready athletic position for a collision. The ideal stable position is:
- Head up, looking in the direction of the coming hit.
- Knees and hips slightly flexed.
- Feet shoulder-width apart.
- Using legs to drive shoulders through the collision.
"In our opinion, the ready position taught by USA Hockey should continue to be taught to young hockey players until further research suggests better interventions targeted at reducing mild [traumatic brain injuries] in youth athletes," the study's authors concluded.
The researchers called for more work to see if the findings also apply to less skilled young players, players with less skilled coaches, and female hockey players.
"Our finding of increasing head impact severity with decreasing anticipation suggests that coaches should target this aspect of ice hockey in their technical development of players during practices, to promote the skills necessary to keep the safety of participants at the forefront."
The study's authors gave the example of "small games" drills that emphasize high speed, quick movements and tasks like passing, shooting and checking in small, confined spaces such as the corner of the rink. These drills are excellent at forcing athletes to play with more awareness that allows them to anticipate collisions, they said.
The study was funded by the Ontario Neurotrauma Foundation, the National Operating Committee on Standards for Athletic Equipment and the USA Hockey Foundation.