An Initial Evaluation of Results from the Balance Tracking System (BTrackS) Single Leg Stance Protocol

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Background: The Single Leg Stance (SLS) test of static balance is a common means of assessing left versus right lower limb asymmetry. Recently, a SLS protocol was made available for the Balance Tracking System (BTrackS) Balance Plate, a low-cost, portable force plate for objective balance measurement.

Research Question: The present study sought to generate an initial set of balance results for the BTrackS SLS test.

Methods: BTrackS SLS tests were conducted on 161 young adults (90 women, 71 men) between the ages of 18 and 29. Participants stood as still as possible the BTrackS Balance Plate for four (2 practice, 2 actual), 20s trials with hands on hips. The first and third trial were performed standing on the left foot, while the second and fourth trials were performed on the right foot.

Results: An ANOVA for Total Center of Pressure (CoP) Path Length (i.e. body sway) found women had better SLS results then men, and that performance improved from practice to actual trials. Analysis of an Absolute Symmetry Index (ASI) measure showed that a difference of 16% or greater between legs (higher than the 10% rule) represented the threshold for asymmetric performance beyond the average adult.

Significance: These results have practical value for those researchers and clinicians using the BTrackS SLS, informing decisions involving the presence or absence typical lower limb symmetry. Additionally, they support the use of a practice trial in the BTrackS SLS protocol and agree with previous results showing sex differences favoring women on tests of static balance.



Balance, Single-Leg Stance, SLS, BTrackS, Lower Limb Symmetry