Association of Y Balance Test Reach
Asymmetry and Injury in Division I Athletes

CA, Chimera NJ, Warren M. Med Sci Sport Exerc. 2015; 47(1): 136-141.

Home Message: Anterior reach asymmetry larger than 4 cm on the Y Balance test
was associated with increased risk of non-contact injury in a sample of
collegiate athletes.

Clinicians need an efficient
and accurate screening strategy that can be used across multiple sports and
genders to identify athletes at risk for musculoskeletal injury. This could
help identify individuals who need interventions to potentially prevent injuries.
The Y balance test,
a measure of dynamic balance during single leg stance, may be an ideal
screening test. This study investigated the link between Y Balance Test results,
collected during pre-participation physicals, and non-contact injuries over the
course of a season. The researchers hypothesized that anterior asymmetrical
reach would be related with increased risk of noncontact lower extremity
injury. Additionally, they thought that a lower composite score would increase
an athlete’s chance of a noncontact injury. Athletes completed the Y Balance
Test scores prior to the start of the season. Throughout the season, the
authors prospectively monitored athletes for noncontact injuries. An injury was
defined as an event where the athlete sought treatment in the athletic training
room and required athletic trainer attention. To assess the association between
Y Balance Test scores and injury risk, the researchers calculated the asymmetry
between left and right sides in the anterior, posterior medial, and posterior
lateral directions by calculating the absolute difference in reach distance
between limbs. Additionally, they calculated a composite score by averaging
right and left reach distances, which were normalized to weight-bearing leg
length. Overall, 81 out of 184 participants sustained a noncontact injury. The
mean composite score was not different between the injured and non-injured
groups and no differences were found for asymmetries in any direction. The
researchers determined that an asymmetry greater than 4 cm was the best
cut-point to identify athletes who sustained an injury but the sensitivity and
specificity were moderate at 59% and 72%, respectively. Based on this cut point,
an athlete with greater than 4 cm anterior asymmetry is more than twice as
likely to sustain an injury as an athlete with no asymmetry. No other
asymmetries were related to a new injury.

This study is the first to
prospectively investigate a collegiate population to assess if Y Balance Test
scores predicted injury incidence. While anterior asymmetry was associated with
sustaining an injury its clinical use as a screening tool, without any other
tests, may be limited. The authors acknowledged a few limiting factors to
consider with this study. Specifically, the definition of injury is not
consistent with other definitions in the literature. While it may be clinically
meaningful to define an injury as needing an athletic trainer’s attention the
athlete may not present with traditional signs of trauma. Additionally, the
inclusion of overuse injuries as a non-contact injury complicates the study
because the onset of symptoms may not coincide with when an athlete reports to
an athletic trainer. It is possible that the Y Balance Test may be an effective
screening tool for acute noncontact injuries but it is difficult to test at
this point. While more evidence is needed, it may be beneficial to collect the
Y Balance test results during preparticipation examinations if time and
resources permit. If an athlete has an anterior asymmetry greater than 4 cm we
should perhaps review his/her chart to see if there are other warning signs
that the athlete may be at an increased risk of injury (e.g., history of
previous injury) and if so develop an injury prevention strategy. Sports
medicine staff should also complete regular surveillance of injury events to
fully understand patterns of injuries in their setting to help identify
characteristics related to injuries like athlete characteristics (e.g.,
balance), training characteristics, teams, or playing surfaces.  

Questions for Discussion: How do you define
injury in your setting? Do you use tools like the Y Balance Test in
pre-participation physicals to aid your understanding of injury risk?

By:  Laura McDonald
by: Jeffrey Driban


Two Clinical Tests for Predicting Onset of Medial Tibial Stress Syndrome

SMITH, C., CHIMERA, N., & WARREN, M. (2015). Association of Y Balance Test Reach Asymmetry and Injury in Division I Athletes Medicine & Science in Sports & Exercise, 47 (1), 136-141 DOI: 10.1249/MSS.0000000000000380