Penn Scientists Find that Coaster G's, Twists, and
Speeds Are Not Enough to Injure the Brain
PA) - To meet the growing expectations of thrill-seekers,
amusement park rides have been built bigger, faster,
and more exciting. But do bigger thrills come with added
risks of injury? Published medical case studies have
proposed a link between roller coaster forces and brain
injury. Already the State of New Jersey has enacted
legislation limiting G forces, and similar legislation
has been proposed by members of the U.S. House of Representatives.
According to a pair of researchers at the University
of Pennsylvania, however, medical science does not
support the notion that roller coasters produce forces
large enough to harm the brains of riders. Their findings
are presented in the October issue of the Journal
"We should step back and separate the facts from
the hype," said Douglas H. Smith, MD, from
the Department of Neurosurgery and the Head Injury Center
at the Penn School of Medicine and co-author
of the study. "To our knowledge, no peer-reviewed
studies have definitively linked brain injury in healthy
individuals to riding the latest, and most powerful
roller coasters. In fact, G forces really aren't the
Most people are familiar with the dangers of G forces
as they affect pilots, as popularized in film and television.
Just as unsuspecting car passengers are forced against
the door during sharp turns, pilots feel accelerations
as they make quick maneuvers - except for pilots, these
accelerations can be as much a five to nine times the
force of gravity (or Gs). The biggest risk of high Gs
is a loss of consciousness as blood pools in the limbs
and away from the brain. But these effects are from
sustained Gs over an average of 43 seconds. High G maneuvers
on roller coasters, however, rarely last more than three
seconds. As the researchers point out, an average person
could momentarily experience eight to ten Gs by plopping
down onto the couch to watch Top Gun.
"What we should be concerned about is not G forces,
but the effects of rapid head acceleration - the rotational
force on the brain that occurs as the body quickly changes
directions," said co-author David F. Meaney, PhD,
of Penn's Department of Bioengineering, "And, when
we predict head accelerations in roller coasters - the
sudden twists and turns - we find that they are well
within established safety margins. It does not appear
that roller coasters produce high enough forces to mechanically
deform and injure the brain."
Using a simple mathematical model, the researchers examined
the three basic features of G forces as experienced
by riders: the magnitude of the force, the direction
of the acceleration, and the time interval over which
the acceleration occurs. They acquired G force data
from three of the most popular and powerful roller coasters
in the country: the "Rock 'n' Roller Coaster"
at the Disney-MGM Studios in Orlando, Florida; "Speed
- The Ride" at the Nascar Café, in Las Vegas,
Nevada; and "Face-Off" at Kings Island, Ohio.
Using this data, they calculated peak head accelerations
in three directions, assuming the head did not strike
Even considering the worst-case scenario, the researchers
found that the largest forces experienced on roller
coasters were far below those that are known to cause
injury. In fact, the damage reported in some published
case reports trauma done as a result of pre-existing
brain injuries. Even in those cases, researchers said
that other factors, such as hypertension from the excitement
of the being on the ride, should be considered.
"The amount of rotational acceleration known to
create injury in the white matter of the brain are roughly
18 times higher than the maximum accelerations calculated
on the roller coasters," said Smith. "For
healthy people who meet the size requirements for the
ride, you are probably safer on the average roller coasters
than driving to the amusement park."
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