Protecting the Knees of Young
By Kerry Putnam, PT, MPT
In the world of sports and sports
medicine, we hear quite a lot about injuries to the knee involving the anterior
cruciate ligament (ACL). One of the four major ligaments of the knee, the
function of the ACL is to help stabilize the knee by preventing the tibia (shin
bone) from sliding forward where it meets the femur (thigh bone).
Injuries to the ACL are common
among athletes who participate in organized sports. However, girls and women
under the age of 25 are four-to-six times more likely
to suffer an ACL injury than young men who participate in the same sport. By
understanding this increased risk and by taking preventive measures, young
female athletes can significantly reduce their risk for ACL injury.
How do ACL injuries occur?
While some ACL problems result from
direct hits or collisions on the playing field or basketball court, the
majority of these injuries occur when a player is landing from a jump or
cutting to abruptly change direction. Approximately 70 percent of ACL injuries
do not involve direct contact with another player.
Why are young women at higher risk
for ACL injuries?
There are a number of
gender-related factors that make ACL injuries more prevalent in young women.
One major factor is that females are wider at the hips and pelvis than men are.
This anatomical difference influences the way women land when they jump. In
order for a woman’s knees to line up over her ankles when she lands, she must
position her thighs inward at an angle. This can result in increased knee
valgus, which means the knees cave in toward each other. When the knees cave
inward, the ACL is stressed and can become injured.
When women land, they also tend to
rely more heavily on their quadriceps (the muscles on the front of the thigh)
than their hamstrings (on the back of the legs). Greater activation of the
quadriceps pulls the shinbone forward, which can stress and injure the ACL.
Additionally, while men tend to land with greater flexion of their knees for
better shock absorption, women tend to land harder and more abruptly, which can
injure the ACL.
We also know that during certain
phases of the menstrual cycle, ligaments (including the ACL) tend to become
more lax and loose. This makes the ACL less effective in stabilizing the knee
and holding it in place properly, which puts young female athletes at higher
risk for injury.
How to prevent ACL injuries?
There are steps you can take to
help decrease your risk for ACL injuries. First and foremost, increase your
core strength with exercises that build your abdominal and back muscles. This
gives your legs a strong base to work from. Increase your hip strength because
the hips control the knee motion; with sufficient strength you can prevent your
knees from caving in.
Build the strength in your
hamstrings. This will help you control your knee flexion when landing, for more
effective shock absorption. Stronger hamstrings also help hold your knee in
proper position, thereby working with the ACL rather than working at
cross-purposes. Finally, improve your jumping and landing technique by
practicing good form. This will increase muscle memory to the point that you
are not required to think about how to jump and land properly while you are
playing because you will have developed the habit of landing correctly.
If you need guidance on proper
jumping and landing techniques or appropriate strengthening and conditioning
for your specific sport, seek the help of a certified athletic trainer or
sports conditioning specialist. Taking preventative measures can help you avoid
unnecessary injury and help keep you in the game.
Putnam holds a master’s degree in physical therapy and is on staff in Cayuga
Medical Center’s Department of Physical Therapy & Sports Medicine, located
at the Island Health Center. Sports medicine is her area of special interest,
and she can be reached at (607) 252-3500.