Laird Harrison
May 09, 2017
Head Injuries Too Common in Female Athletes
A competitive 16-year-old soccer player, Lauren Skeen was leaping for a
head ball when her head cracked into the head of an opposing player. It
was her second such collision, and this time she fell into a grand mal seizure.
Such head injuries are all too common in the world's most popular sport,
particularly for girls. Girls playing soccer suffer 9 concussions per
10,000 games or practices the same incidence as boys playing American
football in US high schools,
researchers at Northwestern University in Chicago have found. And since many concussions go unrecognized, the actual incidence could
be much higher;
as many as half of all players report symptoms.[1]
The
US Soccer Federation and Major League Soccer have responded to the problem, primarily with initiatives to reduce the amount of heading done by children
under age 14, and to remove players with concussions from games.
An
international consensus statement on sports-related concussions, published April 26 in the
British Journal of Sports Medicine, offers scant guidance for prevention in soccer.
A Father's Battle for Protection
To Lauren Skeen's father, Jeff Skeen, the current recommendations fall
far short of what's necessary to protect soccer players. After Lauren's
second concussion in 2001, Jeff (a former employee of Troxel, maker of
equestrian helmets) put together a broad padded headband he thought would
protect his daughter during soccer.
But when Lauren's team made it to the quarter finals of the California
championship a year later, the referee told her to take it off. Once again,
Lauren's head collided with another girl's head. This time, Lauren
suffered such severe disorientation that her parents had to give her wristbands
to tell her where she should be. Recovery took 6 months. "The soccer
community just pissed off the wrong person," Jeff Skeen said.
The Fédération Internationale de Football Association (FIFA),
the international organization that oversees the US Soccer Federation,
no longer prevents players from using the headgear, and some professionals
now use them. But Skeen, who went on to found the Full90 soccer headgear
company, is still battling to force the organization to endorse some sort
of head protection—or to come up with a better solution.
Removing concussed players from games may reduce the harm to those players
caused by further blows or exertion, but it won't reduce the number
of new concussions, Skeen argues. "There is not a single thing that
is being done to eliminate a single concussion other than our headgear," he says.
A Plea for Clinical Trials of Headgear
Faced with a high incidence of anterior cruciate ligament (ACL) tears,
which also disproportionately affect teenage girls, FIFA supported randomized
controlled trials of a series of strengthening and balancing exercises.
The exercises, branded FIFA 11+, were shown to significantly reduce the
risk for this type of injury.[2]
Skeen and others would like to see FIFA support a similar randomized clinical
trial of headgear. But officials say there just isn't enough preliminary
evidence to warrant such an exploration. "In the lab, they haven't
found any great success in terms of reducing concussive forces in this
way," says Bert Mandelbaum, MD, a Santa Monica, California, orthopedist
and assistant medical director of Major League Soccer.
Image courtesy of Full90 Sports
In fact, studies so far support the use of headgear to prevent concussions.
Some confusion stems from the unique way that players' heads are used
in soccer. Intentional heading itself rarely causes concussions because
the ball absorbs most of the energy from the collision.
Only about 8% of concussions in men and 18.3% in women result from contact
with the ball, and most of these appear to be from unintentional contact,
such as when a ball from one field hits a player on another field from behind.[3,4]
In one experiment, FIFA researchers shot balls from a mechanical launcher
at a subject holding accelerometers in his mouth, and found that headgear
made little difference to the movements of his head.[5] Nevertheless, some researchers have worried that repetitive subconcussive
blows might cause cumulative trauma. An average player heads the ball
6-12 times per game and performs at least 2000 headers during a 20-year
career in addition to repetitive heading drills at training.[4]
Efforts to discern neurologic effects from this have produced contradictory results.[4] Researchers examining retired professional soccer players have calculated
increased rates of dementia, possibly due to chronic traumatic encephalopathy
like that suffered by many American football players. But modern soccer
balls, made of synthetic material, are lighter than the leather ones the
retired players may have used throughout most of their careers. And the
brain damage in these players could have resulted from contact with other
hard objects, such as opponents' heads, rather than with the ball.[3]
Protection for Head and Hard Surface Collisions
If intentional heading does cause damage, headgear doesn't seem likely
to protect against it. Researchers have suggested that headgear causes
a change in the radius of the head, which increases both the ball's
moment arm and the head's moment of inertia.[6] That could explain why one study showed that volunteers who headed a soccer
ball 15 times in 15 minutes suffered small but significant short-term
memory losses if they wore headgear, but not if their heads were bare.[5]
Image courtesy of Full90 Sports
While he believes that heading is likely to cause cumulative damage, Skeen
says he didn't design his headgear to protect against head-to-ball
contact because that would change the way the game is played. "We're
trying to make the headgear ignore the head-to-ball impact, because if
you reduce the impact you would slow the rebound speed or direction of
the ball," he says.
Instead, Skeen designed Full90 gear to protect against collisions between
the head and other hard surfaces, such as another head, an elbow, a goal
post, or the ground. As many as 80% of soccer concussions result from
player-to-player collisions, such as "heading duels" of the
type that proved so harmful to Lauren Skeen.[4]
It's common sense that putting something between a head and another
hard surface—such as another head, an elbow, a goal post, or the
ground—will protect the head. FIFA required players to wear shin
guards in 1990 based on little more than such intuitive reasoning.[7]
And a handful of laboratory and observational studies support the idea.
In one study, FIFA researchers outfitted crash test dummy heads with various
types of soccer headgear. Earlier studies had showed that soccer players'
heads sometimes collide at speeds up to 2.5 m/s. So the researchers dropped
one dummy head against another at approximately that speed. They found
that the headgear reduced peak linear acceleration by about a third.[6]
On the basis of this and on angular acceleration, they calculated that
the best of the headgear significantly reduced the risk for concussion
from head-to-head contact. At 3 m/s, the risk was 10% without headgear
and 5% with headgear. At 4 m/s, it was 56% with and 7% without.[6]
At least one study of headgear used in actual games suggests that head
protection could make a difference. Researchers from McGill University
in Montreal collected 278 surveys from soccer players aged 12-17 years.
The surveys ask about concussion symptoms and headgear use. Fifty-two
wore headgear and 216 did not.[1]
The researchers found that 47.8% had experienced symptoms of a concussion
during the 2006 soccer season, although only 15% realized that their symptoms
fit the definition of a concussion. Among those who wore headgear, 26.9%
had experienced the symptoms, compared with 52.8% of those who did not
wear headgear.[1]
The study was retrospective, so it could not control for all variables.
For example, it's possible that the players who wore headgear were
also more cautious to avoid contact with other players. Also, few of the
concussions were diagnosed at the time that they occurred.
But Jeff Skeen finally may get the randomized controlled trial he's
been wanting. Researchers from the University of Madison in Madison, Wisconsin,
have provided headgear to randomly selected high school soccer teams. The
study will include 3000 players and is funded with $300,000 from the National
Operating Committee on Standards for Athletic Equipment, which collects licensing fees on sports equipment sold with its certification.
Will Protective Gear Lead to More Injuries?
Even if a more authoritative study such as this shows strong benefits for
headgear, Dr Mandelbaum says FIFA authorities have other reservations.
"They have learned a few of the lessons that have come from hockey,
where they have seen concussions go up," he says. "All of a
sudden the helmet becomes part of the weaponry."
But introducing protective equipment doesn't necessarily lead to unsafe
behavior, including in hockey. For a prospective study, some hockey players
wore full-face shields and others partial face shields. The incidence
of concussions was higher in the players wearing partial guards.[8]
Jeff Skeen thinks that FIFA is resisting headgear because it wants to preserve
the sport's reputation as safe and affordable. "They don't
want the proliferation of gear," he says. "And they don't
want the discussion about whether any danger could reduce participation."
Wellington Hsu, MD, a professor of orthopedic surgery who led the Northwestern
University study, is also skeptical of the research so far on headgear
in soccer. He doesn't think organized soccer can ignore the problem
of concussions. "I think some intervention is required because of
the number that we're seeing in our study," he says.
A variety of alternatives have been proposed. The finding that girls are
more likely to suffer from concussions than boys leads Dr Hsu to speculate
that neck-strengthening exercises might help.
The new international consensus statement supports"rule enforcement
of red cards for high elbows in heading duels in professional soccer."
In a more radical approach,
researchers at Cincinnati Children's Hospital Medical Center have proposed a collar that constricts the jugular just enough to increase the volume of blood
in the cranium and reduce the amount the brain can slosh. While imaging
studies show protective effects on the brain, the collar has not yet been
shown to reduce actual concussions.
For his part, Skeen plans to keep pushing his headgear. It's not about
making money, he says. He has lost money on every unit sold for the past
15 years and will gladly get out of the business if Nike or Adidas takes
his place. "I just think that the number of head injuries needs to
be reduced or the sport will die."