Anterior Cruciate Ligament (ACL) tears are one of the most
common knee injuries suffered by athletes, but they are significantly more
prevalent in young, female athletes. I
would know…I have torn both of mine. As
an NCAA Division I volleyball player, I worked my way up the ranks from playing
in high school, at the club level, and even at a junior college. Never once was I screened for deficits that
could lead to a catastrophic injury like and ACL tear. Maybe if I had, I would not have needed 5
knee surgeries total, including two ACL reconstructions.
The ACL attaches from the posterior (back) of the femur
(thigh bone) to the anterior (front) tibia (shin bone) and its main purpose is
to limit anterior translation (forward gliding) of the tibia. It also helps to limit excessive internal and
external rotation (turning) of the tibia.
Thus, the main mechanism of injury for an ACL tear is hyperextension of
the knee causing anterior translation of the tibia combined with a rotational
force…often seen when an athlete plants their foot and pivots simultaneously.
Why do young female athletes suffer ACL injuries four to six
times more often than their male counterparts?
There is a biomechanical angle measured through the hip and knee called
the “q-angle” that shows the relationship between the hip and knee. Females have a larger q-angle because we tend
to have a wider pelvis than males. The
wider pelvis causes a more valgus orientation of the knee (see the picture
below). That valgus orientation puts
significant pressure on the medial (inside) of the knee and ultimately changes
the biomechanical efficiency of the knee joint itself. The increased valgus forces put excess
pressure on the stabilizing ligaments in the knee, like the ACL, and increase
the natural rotation of the knee. There
is evidence that also contributes a lack of core stabilization ACL
injuries. Decreases in core
neuromuscular control can increase uncontrolled truck displacement which leads
to higher knee ligament strain and ACL injury.
A good way to identify athletes at risk of an ACL injury is
to do a screening test, such as the Tuck Jump test. This test requires the athlete to complete
repetitive tuck jumps (jumping while tucking the knees toward the body) over
the course of 10 seconds and the person screening should look for the athlete’s
tendency to land with their knees in a valgus orientation which identifies a
neuromuscular imbalance that needs to be addressed.
The increased valgus orientation of the knees is often
caused by increased firing of the quadriceps and decreased activation of the
gluteal muscles. A great way to
reactivate the glutes is to perform the exercise below.
Hip Bridge with
Resistance Band:
Begin by lying on the floor with knees bent and feet flat on the floor. Place a resistance band around the thighs
just above the knees. Slightly abduct
the legs (separate the knees) while simultaneously performing a hip bridge
(bringing the hips off the ground).
Slowly lower to start position without bringing the knees together. Perform 3 sets of 10 repetitions.
Valgus collapse of the knee can also be contributed to weak
hip abductors and external rotators, like the gluteus medius. Performing the clamshell exercise will help
strengthen those muscles.
Clam Shell with
Resistance Band:
Begin by lying on the side with knees together and bent at 90 degrees with the
resistance band around the knees. Lift
the top knee upward while keeping the feet touching. Continue lifting the knee to the point just
before the pelvis begins to move. Lower
the knee back to the starting position.
Perform 3 sets of 10 repetitions with each leg.
The hamstring muscles work with the knee to help counteract
the contraction of the quadriceps and prevent excess anterior translation of the
tibia. The stability ball leg curl
exercise helps activate the hamstrings while also activating the core muscles.
Stability Ball Leg
Curl:
Begin lying face up with arms extended at your sides and ankles on top of the
stability ball. Active core and form a
bridge position. Then flex your knees,
bending your legs as you draw the ball inward.
Reverse the movement, extending your knees, and return to the start
position. Perform 3 sets of 10
repetitions.
Lateral stability plays a large role in the ability of the
female athlete to control lower extremity alignment. “Monster Walks” are a great way to boost
lateral stability.
“Monster Walks”:
Begin standing with a resistance band around the thighs just above the
knees. Keep your feet and ankles apart enough
to put resistance on the band. Perform a
¼ squat with both feet supporting your body weight. Hold the squat position, shift weight fully
onto one leg. Take a lateral (sideways)
step with the un-weighted leg. Repeat,
taking several lateral steps in one direction and then doing the same in the
opposite direction.
Yet another potential risk for ACL injury comes when landing
with knees bent less than 45 degrees.
Therefore, landing training is a very important part in injury
prevention.
Long Jumps to
Backward Hop:
Begin in ¼ squat position. Jump forward
in an explosive long jump trying to “stick” the landing for 3-5 seconds. Make sure the knees are flexed to
approximately 90 degrees on landing. Hop
backwards two or three times returning to the start position. Perform 3 sets of 10 repetitions. If the athlete is unable to “stick” the
landing with toes straight ahead and no inward knee motion, then regress them
to submaximal jumps of a shorter distance until perfect technique can be
attained.
Incorporating high intensity plyometric jumping exercises
into a training plan has been shown to significantly reduce the incidence of
ACL injury. Performing split jumps gives
these plyometric benefits.
Split Jumps:
Begin in a split stance lunge position with arms raised at shoulder level. Jump upward and quickly reposition the legs
and land with feet in opposite positions.
Raise arms while you are jumping.
Continue jumps by alternating leg positions. Perform 3 sets of 10 repetitions. If the athlete fatigues to the point where
she cannot perform the exercise perfectly, she should be instructed to
stop.
Be sure to record the duration of each competed exercise
with the goal of the next training session to continue to improve technique and
increase volume and intensity. Also,
repeat the screening test every few weeks to determine progress. Give the athlete feedback with verbal cueing
before and after training so they can make the necessary changes for
improvement. It is imperative to include
a core stabilization program with the above training exercises to create a
well-rounded program and reduce the risk of injury from all angles.
If you or someone you know in the Gallatin Valley area is
looking for a chiropractor, please call Dr. Shea Stark with Pro Chiropractic at
406-219-2462 to schedule an appointment in our Belgrade, Manhattan, or Bozeman
office. Dr. Stark is a board certified
chiropractor and the author of this blog post.
To learn more about Dr. Stark and the many benefits of chiropractic
care, please visit our website: www.prochiromt.com.
