ACL injuries in girls

As we move to warmer weather we can now really begin to enjoy the outdoors, which means lots of youth sports.  I say great–but I also will take a moment to discuss concerns about the absolute epidemic of anterior cruciate ligament (ACL) injuries in adolescent female athletes.  Over the past generation we’ve seen increasingly frequent ACL injuries by up to 900% due largely to the explosive growth of girls sports since Title IX; anywhere from 20,000-80,000 occurrences yearly.  Soccer, basketball, and gymnastics cause the most injuries; girls are up to 8x greater risk compared to boys.

Some background: the ACL is inside the knee and keeps the tibia (shin) from sliding forward relative to the femur (thigh) during ambulation.  >70% of injuries result from no contact with other players but rather from some sudden, awkward movement.  One example: a girl plants her right foot with extended knee and then tries to quickly cut right.  With sudden deceleration her weight is back with leg straightened moving under her upper body as her torso turns right and out and her thigh rotates inward(counterclockwise) and POP!! (there is often a loud snap that everyone close to the injured girl will hear when the tear occurs).  This is a common mechanism of injury.

There are many physiologic factors contributing to girls’ ACL risks:

  • Hormones–testosterone surge in boys makes for greater muscle development allowing boys to control movement more with muscle strength; girls tend to rely more on bones and ligaments.
  • Menstruation-the ACL actually gets slightly longer and more lax mid-cycle creating greater risk
  • Neuromuscular factors–quadriceps (front thigh):hamstring (back thigh) muscle strength ratio is greater in girls compared to boys.  This puts greater strain on the ACL.  Girls also tend to have one leg stronger than the other compared to boys more symmetrically distributed leg strength which creates more problems in the weaker leg.
  • Girls tend to run and land relatively flat footed.  Boys are up on their forefoot more which is a better shock absorber.
  • Girls have relatively less core body strength.
  • Wider pelvis makes for more uneven landing

Note that for both boys and girls being overweight increases risk.

There are many steps we can take to avoid ACL tears.  Proper fitting quality footwear for their sport is a nice start.  Core strengthening is key–lots of sit-ups and planks.  Neuromuscular training is a very important component.  Here is an excellent program.  A variation on that program is demonstrated here.  So besides dribbling, passing, shooting and SCORING, make these exercises a regular part of your daughter’s training routine, especially off and pre-season.

Chance of ACL injury does not at all mean that your daughter should shrink from enthusiastic participation and aggressive competition.  Like all risk it must be balanced by advantages and can largely be controlled by proper lifestyle.  Sports will help make her more confident, stronger, healthier and so often happier.  And most importantly–IT’S FUN!!  So get out there and play.

Send along questions and comments, and thanks for following.