by Mike Grafstein.
(Guest Author)

As soccer is growing in popularity more and more young males and females
are playing the game. The scary part of this is that female soccer players
have a higher incidence of tearing their ACL. In fact there have been
reported cases of twelve year old girls tearing their anterior cruciate
ligament.

So what exactly is this ACL (anterior cruciate ligament)?

The ACL is the major ligament located inside the knee joint. It prevents too
much twisting of the femur (thigh bone) on the tibia (shin bone) when a
player has to stop and change direction in a soccer game or landing from a
50-50 ball on one foot.

There are several factors that are believed to predispose females to ACL
injuries. This includes structural/anatomical, biomechanical and
neuromuscular factors. So let’s take a look at what some of the factors might
be that lead to this terrible and possible career ending injury.
Structurally the female ACL tends to have a decreased thickness as
compared to a male’s ACL. This has been documented by magnetic
resonance imagining (MRI).

Females also have a greater ‘Q angle’ than males. The Q’ angle is an angle
formed by an imaginary line extending from the anterior superior iliac spine
(bump on the front of the hip bone) to the midpoint of the patella (knee cap)
that is bisected by a line from the tibial tuberosity (bump below the knee
cap) through the midpoint of the patella (knee cap).

Athletes that have a Q’ angle above an average of 15 degrees have leg
postures that create excessive external (lateral) rotation of the tibia (shin
bone). This creates a greater valgus stress at the knee joint (knocked
knees). In other words it causes the thigh bone and shin bone to separate.
In a dynamic situation, as in abruptly stopping and changing direction, the
knee joint may be predisposed to a position of neuromuscular loss of control
causing inactivity of the hip muscle stabilizers (gluteus muscles and hip
lateral rotators) leading the ACL to a point of no return. The stabilizing
muscles of the hip are lengthened and therefore lose the ability to contract to
maintain proper hip and knee alignment.

Next there appears to be a problem with hamstring muscle activation.
Hamstring muscle activation controls the amount of anterior translation
(forward motion of the tibia). There is a significant decrease in stress on the
ACL with proper activation. It is the decrease of hamstring activation in
landing that may lead to ACL injuries; therefore it is important to train proper
jumping mechanics. Now we need to create exercises that challenge the
predisposing factors leading to an ACL injury.

Any good ACL injury prevention program for soccer must start with building
base hip and knee strength. The movement of the exercises should be similar
to the movement on the soccer field. I highly recommend soccer players
avoid building strength with exercise machines. These machines have a
tendency to isolate single muscles that may lead to other injuries and muscle
imbalances.

The squat is a great lower body exercise that builds strength around the hip,
knee and ankle joints for example. My favorite for the lower body is the
single leg squat as it encompasses strength, power and stability and don’t’
forget most of the game is played on one leg!

Next I recommend some type of agility exercises as part of an ACL
prevention program. In a soccer game the feet move in many different
directions. You know we all can move forward and backward but soccer
players must also be able to work from side to side, stop and change
direction.

Proper landing is very important for female soccer players. It is key to
“activate” the hamstring muscle. In some areas of sports the hamstring
muscle is known as the dynamic ACL. A gradual progression from jumping up
to a bench with a “soft” landing to continuous jumps over hurdles or benches
needs to be put into an ACL prevention program.

Core work also needs to be implemented to stabilize the muscles around the
hip. If the core is weak there will be a lot of shifting of the pelvis and this will lead to an ACL tear.

Finally, proper cardio fitness is important. Soccer has become more of a
power and speed game. Sending young female soccer players out for a
fifteen to twenty minute conditioning jog will do three things 1) make them
slower, 2) make them weaker and 3) predispose them to overuse injuries.
These girls need some interval training runs where they alternate the pace of
their run from a steady state jog to an all out sprint several times in a twenty
to thirty minute period with changes of direction. This type of conditioning is
similar to the activity in a soccer game.