Monday, August 12, 2013

Can Dynamic Balance Predict Noncontact Injuries in Athletes?

In the August 2013 issue of Sport Health: A Multidisciplinary Approach, there was a great article entitled “Dynamic Balance Performance and Noncontact Lower Extremity Injury in College Football Players”.  If you have viewed any of our previous articles, you know that injuries sustained in athletics can and will lead to long term joint issues, potential surgery and increased downstream health care costs.  When you look at the statistics related to injuries in athletes, the numbers really are staggering. 

According to the U.S. Centers for Disease Control (CDC), participation in organized sports is on the rise. Nearly 30 million children and adolescents participate in youth sports in the United States. This increase in play has led to some other startling statistics about injuries among America's young athletes:

·        High school athletes account for an estimated 2 million injuries and 500,000 doctor visits and 30,000 hospitalizations each year.1

·        More than 3.5 million kids under age 14 receive medical treatment for sports injuries each year.1

·        Children ages 5 to 14 account for nearly 40 percent of all sports-related injuries treated in hospitals. On average the rate and severity of injury increases with a child's age.4

·        Overuse injuries are responsible for nearly half of all sports injuries to middle and high school students2

·        Although 62 percent of organized sports-related injuries occur during practice, one-third of parents do not have their children take the same safety precautions at practice that they would during a game.2

·        Twenty percent of children ages 8 to 12 and 45 percent of those ages 13 to 14 will have arm pain during a single youth baseball season.3

·        According to the CDC, more than half of all sports injuries in children are preventable.

·        Among athletes ages 5 to 14, 28 percent of percent of football players, 25 percent of baseball players, 22 percent of soccer players, 15 percent of basketball players, and 12 percent of softball players were injured while playing their respective sports4

·        Since 2000 there has been a fivefold increase in the number of serious shoulder and elbow injuries among youth baseball and softball players.4

Hence why prevention of injuries is and needs to be a major focus.  In this study, the authors looked at the Star Excursion Balance Test (SEBT) to see if this could be used with college football players to predict those that are at risk for injury.  The SEBT has been used for years to predict injury in athletes and studies have shown that asymmetries in scoring between the right and left can be used to predict those that are at risk. 

In this study authors looked at 59 college football players.  SEBT was performed on each player at the beginning of the football season.  In performing this test, the athlete stood in single limb stance and performed the SEBT on each limb.  3 repetitions of each of the movements were performed with measurements for each movement determined.  The SEBT was performed on both limbs and composite scores were determined for each limb and compared.  Non-contact lower extremity injuries were recorded over the course of the season by the head athletic trainer.

What the authors found was that if a player scored below 89.6% of the contralateral (opposite) limb then they were 3.5 times more likely to get injured.  This means that poor performance on the SEBT (or poor dynamic balance) was related to increased risk for sustaining a noncontact lower extremity injury over the course of the football season.  This tells us that this may be a very easy way to identify those athletes that are at risk or at least at greater risk for injury.     

This supports similar findings in an unpublished study done in 2009.  In this study, over 3 years, authors screened over 700 high school and college athletes.  In this study, they compared the Functional Movement Screen (FMS), SEBT and the 12” jump drop test to assess which had a higher predictive value for athletic injury and which was the most efficient to use in physicals.  What the authors found was that the SEBT was the most predictive and the most efficient screen to use in mass high school and college physicals.

Knowing that the SEBT is such a valuable tool, it should be done as it is described in the research.  This is mentioned because some authors have suggested that the Y-test (a cheaper alternative) is a comparable test to the SEBT.  However, it should be mentioned that the SEBT and the Y-test are not the same.  These two tests are fundamentally “very different” and therefore the research data that is associated with the SEBT cannot be used to validate the Y-test.  The reason for this is that the SEBT is a single limb test, if single limb test is defined as the contralateral limb “not contacting” the surface.  With the Y-test, the subject stands on one limb while pushing the measurement device with the contralateral limb.  Although this is supposed to be done with light force, this in fact results in both limbs contacting a surface which not only provides stability but also proprioceptive feedback.  As a result, this is not a single limb test when one defines it as the contralateral limb “not” contacting a surface.  As a result, the data from the SEBT correlating variances in limb measurement cannot be used to support variances seen with the Y-test.  These are two completely different tests and hence the results would be different.

1.      JS Powell, KD Barber Foss, 1999. Injury patterns in selected high school sports: a review of the 1995-1997 seasons. J Athl Train. 34: 277-84.
2.      Safe Kids USA Campaign Web site. 2009.
   3.      American Academy of Orthopaedic Surgeons. 2009.

4.      Preserving the Future of Sport: From Prevention to Treatment of Youth Overuse Sports Injuries. AOSSM 2009 Annual Meeting Pre-Conference Program. Keystone, Colorado.
5.      Petty, D; Robinson, K; Nessler, T.  Functional Movement Screen, Star Excursion Balance Test or 12” Drop Test: Which screen is more effective for prevention of injuries in high school athletics? 2009
6.      Butler R, Lehr M, Fink M, Kiesel K, Plisky P.  Dynamic Balance Performance and Noncontact Lower Extremity Injury in College Football Players.  Sport Hlth.  Published online before print.  Aug. 2013.

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