Monday, December 5, 2016

Challenging the Status Quo - Part IV

Over the course of the last couple of weeks, we have been providing some clinical commentary on what we have learned in 20 years of clinical practice and over 15 years in movement assessment.  Obviously, we can't encapsulate everything we have learned in a blog or two but we can provide some insights.  We have begun to discuss in detail, over the last 2 weeks, that we need to recognize where the flaws are in our current ways we assess so we can do things better.
During the last 2 weeks we went into depth on some movements we can look at and what the research tells us about how we should look at them.  Assessing these movements as described in the literature should and will guide our specific interventions.  At the beginning of this section, we highlighted what we know are well documented movement risk factors.  As a point of reference, these are:
The above referenced articles are only a few of the large number of studies showing the same thing. So although there is only one referenced here, these are some of the more current ones that have been done over the last 10 years highlighting the same risk factors.  Based on the literature, we know several things.
  1. Frontal plane motion of the knee greater than 10 degrees in motion is bad!  The larger the magnitude of this motion, the worse it is.  An athlete that has 20 degrees of frontal plane motion is at greater risk than an athlete with 10 degrees of frontal plane motion.
  2. Speed at which this motion occurs is a risk factor!  An athlete that has10 degrees of motion that occurs slowly is at less risk than an athlete that has 10 degrees that happens very fast.  Although we have not published this, some guidelines we see are: 
    •   In a single leg squat if valgus occurs at >20 degrees per second, then the athlete is at greater risk
    • In a single leg hop if valgus occurs at >100 degrees per second, then the athlete is at greater risk
  3. >20% variance in single limb symmetry is bad!  Keep in mind, an athlete can move equally bad on both legs so although, in this scenario, they are symmetrical, it is still bad.  But overall, a >20% variance is bad.  Larger the variance, the greater the risk.
  4. Asymmetry (shifting weight to one side) during the squatting motion is bad!  Whether you call it a lateral shift or lateral displacement of the pelvis during a squatting motion, this has a direct impact on force attenuation and force generation.  The larger the asymmetry is during the squat the greater the risk is.   
  5. Inability to maintain core stability within 10 degrees is bad!  This should be assessed for the ability to maintain stability in flexion/extension and rotation. 
In addition to the above, we also know there are demographic risk factors that should be considered.  

Considering all the above, then we should take a look at the standard of practice for movement assessment in athletics.  Remember the intent is to question the status quo so that we can do what we do better.  At the end of the day, we are not concerned about offending people, but rather prevent more injuries in our athletes!  As such, most would agree the most commonly used movement assessment today is the Functional Movement Screen or FMS.  For those of us familiar with the FMS, we recognize that the research based risk factors noted above is not assessed using the FMS.  Looking at some of the specific movements:

  • Overhead squat - assesses several factors but is not assessing lateral displacement of the pelvis or lateral shift
  • Hurdle step & In-line lunge - although they are measuring asymmetry of motion assessed with the FMS, it is not assessing magnitude or speed of frontal plane motion of the knee during SL performance or the asymmetry of this frontal plane motion.
  • Trunk stability and rotational stability test have little research support related to their correlation and core stability in sport.
In addition to the above, some additional challenges:

  • Fatigue not assessed.  Does 3 repetitions performed with each exercise give a true picture of what the athlete looks like in sport.
  •  Demographic risk factors not considered in overall risk rating.
  • Composite score of 21 is not sensitive enough to detect minor improvements in movement.
Considering the above, then the results of some of the current research is not a surprise.  Some of the current studies include:

  • Bardenett et al - Int J Sports Phy Ther 2015 - looked at the FMS as a predictive tool in high school athletes.  Of the 167 high school athletes that were assessed during the pre-season, the results showed the FMS was good at recognizing asymmetry in the movements tested.  But they found that the results were not a good at predicting injury.
  • Dorrel et al - J Ath Train 2015 - performed a systematic review and meta-analysis of research from 1998 to 2014.  What the results showed was that the FMS demonstrated low predictive validity for injury prediction and leading the authors to conclude that this should not be used for injury prediction.
  • Bushman et al Am J Sports Med 2016 - looked at the FMS as a predictive tool in active male soldiers.  Of the 2476 soldiers assessed, the FMS demonstrated low sensitivity and low positive predictive value.  This lead the authors to conclude this could lead to misclassification of injury risk in military personnel.  If they are assigned to hazardous duty as a result of this misclassification, it could potentially place the soldier at greater risk.
  • Frost et al J Strength Cond Res 2013 - did the FMS on healthy firefighters and scored each on the assessment.  This was followed 3 minutes later by performing the test again but just prior to testing each firefighter was instructed on what they were being scored on.  Each participant had an average of 2.6 point (12.4%) improvement in their overall score with just knowledge of how the test is scored. 
  • Wright et al Bri J Sports Med 2016 - in this clinical commentary based on the literature review showing a low sensitivity of 24% led the authors of this paper recommending that this should not be used for injury prediction or for making return to sport calls.
Despite all the above, the FMS has been instrumental in advancing what we know about movement and screening for risk.  The FMS and the developers behind it have been instrumental in the creating this shift to look more closely at movement.  As a result, the positive impact they have had on the field and injury prevention is immeasurable.  But as a science, we must advance based on what we know.  Consider, can we do it better?

We hope you enjoyed this week's commentary and hopefully it provoked some new thoughts.  Next week we will close this out with looking at not over complicating movement and raising the standard of practice. 

Dr. Nessler is a practicing physical therapist with over 17 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >3000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training. 

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