Incidence and Risk
Factors for Injuries to the Anterior Cruciate Ligament in National Collegiate
Athletic Association Football: Data from the 2004 – 2005 Through 2008 – 2009
National Collegiate Athletic Association Injury Surveillance System

JL, Braun HJ, Durham JL, Chen MR, & Harris AHS. The American Journal of
Sports Medicine. 2012; 40: 990-995.

athletes experience a high rate of sport-related injuries including injuries to
the anterior cruciate ligament (ACL).  Epidemiology
data may help us understand when these injuries are most likely to occur.  The purpose of this study was to determine
the incidence and epidemiology of football ACL injuries utilizing the NCAA
Injury Surveillance System (ISS) for a five year period (seasons 2004-05
through 2008-09).  The NCAA ISS contains
athletic exposures and injury data reported by athletic trainers from
participating NCAA institutions (any of the 3 NCAA divisions).  During the 5 year period, 318 ACL injuries
occurred in NCAA football athletes.  The
overall ACL incidence rate was 1.42 per 10,000 exposures.  Rate of ACL injury was highest during
postseason (1.55 per 10,000), when compared to pre-/in- season.  Furthermore, an athlete was 10 times more
likely to injure their ACL during a game (8.06 per 10,000) when compared to
practice (.8 per 10,000).  ACL injury
rate on an artificial turf was 1.3 times higher than natural grass.  Reported mechanisms of injury were player
contact (53%), non-contact (40%), and ground contact (4%). 

it appears that ACL injuries are far more likely to occur during a football
game when compared to practice.  Is it
the speed or intensity that games are played in comparison to practice?  Or could it be related to the fatigue of high
level game activity compared to practices? 
The mechanisms of injury consisted of player contact as well as
non-contact mechanisms.  The most common
ACL mechanism in a general population is non-contact, but the contact nature of
football seems to add to the increased risk of ACL injury when compared to
athletes participating in other sports. 
It would be interesting to analyze the contact mechanisms in more
detail.  Another interesting thing to
consider is that football athletes vary in size and sport demands, largely
influenced by position.  There was not
enough data collected to compare incidence rates by position (since this was
only collected in the game data). Observationally, ACL injuries were most
commonly reported in linebackers, running backs, and special teams
players.  Could it be a sport task
specific to these positions such as turning and cutting that is associated with
the increased risk of ACL injuries? 
Further research may be able to provide insight to what predisposed
these positions to ACL injuries.  Injury
rates may be confounded when playing a game on artificial turf.  There was mention of a significantly greater
rate of injury on the newest generation turfs in comparison to earlier turf
fields.  Many institutions seem to be
installing turf fields due to their all-weather use and long-term upkeep.  If these newest generation turfs are more
“like grass” what is it about them that is seemingly causing more injury?  Given the contact nature of football, is
there anything that clinicians can do to target prevention of ACL injury
efforts in football players?

by: Nicole Cattano

Dragoo JL, Braun HJ, Durham JL, Chen MR, & Harris AH (2012). Incidence and risk factors for injuries to the anterior cruciate ligament in national collegiate athletic association football: data from the 2004-2005 through 2008-2009 national collegiate athletic association injury surveillance system. The American Journal of Sports Medicine, 40 (5), 990-5 PMID: 22491794