Last week we looked at
positions that we know put the hip at risk for femoral acetabular impingement
(FAI). We concluded the last blog by
asking the question, should we look at the previously mentioned movements (adduction,
internal rotation and flexion) that occur in the lower kinetic chain during
weightbearing motions so we may identify those at increased risk for FAI?
To answer that, we first have
to see is what do these movements look like during full weightbearing? How might that movement be represented, for
example, in a full squat? Since this is
such a common exercise in sports and has such a high correlation to athletic
performance, it would make sense to look at the squatting position. In this example (pictured here), we can see
an athlete that is demonstrating a lateral shift to the right. This lateral shift, will result in greater hip
flexion and a greater degree of adduction at the right hip versus the
left. This brings the greater trochanter
and intertrochanteric line of the femur in closer proximation to the acetabular
labrum. Both of these movements combined,
under full weightbearing positions could result in FAI of the right hip. If this lateral shift is present under full
body weight conditions, we can predict that these motions will be similar or
even slightly worse under higher loading conditions (squatting with
weight). That being said, if this motion
is never identified and/or corrected, then there is a high probability that it
will remain no matter what surgical technique or intervention is performed to
aid in treatment of the FAI. But, one
movement alone will not give us enough information about what our intervention
should be. So are their additional
movements we can look at?
In the 2011 American
Journal of Sports Medicine, Grindem et al showed
that single limb testings was a better predictor of function than bilateral
testing. Myers et al, in 2012,
showed that asymmetry in single limb performance was a better indicator of risk
and Kristianslund et al,
in 2013, showed that single limb performance was a better indicator of risk in
sport. So considering these as well as
numerous other studies, it would make sense to assess single limb performance
for potential risk for development of FAI.
In this example (pictured here), we can see an athlete demonstrating
adduction, internal rotation during a single leg squatting activity (flexion of
the hip). The combination of these
motions again brings the greater trochanter and intertrochanteric line of the
femur in closer proximation to the acetabular labrum. Under single limb weight bearing positions,
the pressures at the joint are much greater than bilateral testing and could
give a better indication of risk for FAI.
Just using these two
movements alone (squat and single leg squat), we can see some potential
opportunities for strengthening of the system that could lead to a reduction of
the lateral shift and adduction and internal rotation that is observed. So how do we address these?
There are multiple ways to
address this which is beyond the current scope of this paper and which has been
discussed in detail in our previous blogs.
Whatever we do from a training perspective, we should have one thing in
mind, train to reduce the movements associated with risk that my athlete may
present with during athletic participation.
That said, we do want to mention what you should NOT do from a training perspective.
During our training programs, our
goal should be to perform closed kinetic chain functional activities (like
squats) which develop motor learning patterns similar to what we want to see
during activity or sport. What we know,
is that in athletics, there are certain movements that put athletes at
risk. Our goal should be to train
movement patterns which PREVENT these movements.
Pictured here is a common
exercise used to improve movement during the squatting motion. In athletics, we know one of the main risk
factors for ACL injuries as well as FAI is adduction, especially if this occurs
during the squatting motion or during single limb activity. This exercise, as performed here, is teaching
the athlete to adduct their knees during the squatting motion. By placing the ball between the knees, the
athlete must squeeze the ball to prevent it from falling. What is trained is a motor plan that says,
when I squat, I want to adduct my knees.
This is the exact opposite of what we should be training. This same exercise, performed with a band
around the knees (pulling the knees into an adducted position) would cause the
athlete to abduct their knees during the squatting motion. Training in this way will create a motor plan
that says, when I squat, I want to abduct my knees. By creating this motor plan and strength, the
athlete will then decrease the adduction that occurs during the squatting
motion and therefore decrease the stress to the acetabular labrum and the ACL.
So, what ever we do from an
assessment perspective or a training perspective, thinking about the movements
can guide not only how we assess but also how we train? To assess
properly will tell us if our interventions are making an impact and will also
guide our training interventions. To do this well, will result in
improved movement in our athlete during athletic participation and overall
improved athletic performance. We hope
that you found this blog insightful and useful. As we stated previously,
stay tuned and if you like what you see, SHARE THE PASSION! It is the
biggest compliment you can give. Follow us on Twitter @ACL_prevention and
tweet about it. #DMAOnTheMove and help us spread the passion and
#movementonmovement.
Build
Athletes to Perform…Build Athletes to Last!™
Trent Nessler, PT, MPT, DPT: CEO/Founder ACL, LLC | Author | Innovator in Movement Science and
Technology. Dr. Nessler is a physical therapist and CEO/Founder of
ACL, LLC. He is the researcher and developer the Dynamic Movement Assessment™, Fatigue Dynamic Movement
Assessment™, 3D-DMA™, author of the textbook Dynamic Movement
Assessment: Enhance Performance and Prevent Injury, and associate
editor for International Journal of Athletic Therapy & Training.
For more information, please see our website at www.aclprogram.com
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