The news is filled with reports of athletes who have sustained concussion. Football comes immediately to mind, but plenty of other sports carry the risk of traumatic brain injury, including:
In terms of concussion, for boys and men the riskiest sport is football, which by definition involves repeated impacts. Although it may be intuitive that older children play harder and are more likely to be hurt, a 2013 report from the Institute of Medicine estimated that high school football players were more likely to suffer a concussion than college players. (High school players had 11.2 concussions for every 10,000 games and practices; college players had 6.3 concussions per 10,000 games and practices.)
In the pros, where a running player can tackle a stationary one at speeds of about 25 miles an hour, concussion is a well-known crisis. A professional football player may receive more than 1,000 blows to the head during a single season, and in the tough-guy football culture it’s likely that at least some of those blows are unreported concussions.
It’s important to note that helmets, which are almost universally worn in football, offer protection against skull fractures but not against concussion. A well-made helmet can prevent the skull from cracking upon impact against the ground or against another player, but it cannot stop the brain from moving within the skull. That movement, especially the rotation of the brain within the skull, is what causes traumatic brain injury. (See What Is a Concussion?)
For girls and women, soccer is the sport that has the highest concussion risk. This could be simply because girls and women aren’t likely to play football – if they did, that would probably be their riskiest sport as well. Soccer may not involve as much player-to-player impacts as football does, but players who “head” the ball sustain impacts of up to 70 miles an hour when they do.
Boys and men suffer concussions in soccer too, but not at nearly the numbers their female counterparts do. Some studies suggest that females are twice as likely to sustain a concussion as males, although the reasons for that are not clear.
Twenty years ago it was extremely rare to see a skier wearing a helmet. Neither Sonny Bono nor Michael Kennedy was wearing one when they died in ski accidents a few days apart in early 1998. The following year, the U.S. Consumer Product Safety Commission recommended that all skiers wear helmets. In the years since then, more and more skiers have taken to wearing them – by some estimates as many as 60 or 70 percent of skiers and snowboarders now wear helmets.
As with football helmets, however, ski helmets provide better protection against skull fractures than they do against concussion and other traumatic brain injuries. (Natasha Richardson was not wearing one when she fell on a bunny hill in 2009 and suffered a fatal brain injury.) Concussion can occur even at low speeds, but the high speeds attained by some skiers and snowboards create an extremely high risk for a concussion or other brain trauma in the event of a fall or a crash.
Ice can be a particularly unforgiving surface – and for a skater, there’s nowhere else to go in a fall. Figure skaters, speed skaters, and hockey players are all at risk, as they can hit the ice at speeds of 20 to 30 miles an hour. As with other athletes, skaters who fall on the ice can suffer the impact plus rotation that define concussion.
It’s worth noting that speed skaters and hockey players typically wear helmets – they do not protect against concussion any better than they do in other sports, but they do help prevent skull fractures. Figure skaters, who participate in a sport where grace and beauty are part of the winning combination, do not wear helmets and are thus at risk not only for concussion but for fractures as well.
An American Association of Neurological Surgeons (AANS) study looked at 2009 data from the Consumer Product Safety Commission to analyze trends in emergency room visits for traumatic brain injuries. The number one recreational activity that sent participants to the ER for a head injury was not football, soccer, or skiing – it was bicycling. At more than 85,000 head injuries, bicycling sent almost twice as many people to the ER than did football, its distant second at 47,000.
Even worse, the CPSC found that as helmet use increased among cyclists, the rate of traumatic brain injuries increased. It is unknown whether riders engage in riskier behavior when they’re helmeted, believing themselves to be safe from injury while wearing a helmet.
Cyclists can suffer concussion or other TBI when they are struck by a car, hit a pothole or other surface irregularity, or get knocked off their bike some other way. A cyclist who gets thrown over the handlebars (a common scenario when the bike stops short or the rider hits the front brake) will continue traveling at the speed of the bike in the moment before the crash – and even a cyclist traveling at moderate speed could be going 12 to 15 miles an hour.
Even though about half of all cyclists these days wear bike helmets, their risk of concussion is not reduced. As with other helmets, bike helmets protect against skull fractures, not concussion.
It's not surprising that a gymnast who hits his or her head on the balance beam during a flip or dismount may suffer a concussion. Likewise a bad fall off the parallel bars, or a vault gone wrong, could also lead to a concussion-causing impact.
It’s less intuitive, though true, that a gymnast (or a cheerleader) could suffer a concussion without having any accident at all. A forceful dismount, even one that’s perfectly “stuck,” could create enough force in the athlete’s brain to cause a concussion. Remember that it’s the soft tissue of the brain striking against the inflexible inside of the skull that causes the damage.