Efficacy of the Star Excursion Balance Tests in Detecting Reach Deficits in Subjects With Chronic Ankle Instability

Abstract

OBJECTIVE: Chronic instability after lateral ankle sprain has been shown to cause balance deficits during quiet standing. Although static balance assessment in those with ankle instability has been thoroughly examined in the literature, few researchers have studied performance on more dynamic tasks. Our purpose was to determine if the Star Excursion Balance Tests (SEBTs), lower extremity reach tests, can detect deficits in subjects with chronic ankle instability. DESIGN AND SETTING: We performed all testing in a university athletic training facility. We tested lower extremity reach using the SEBTs, which incorporates single-leg stance with maximal reach of the contralateral leg. SUBJECTS: Twenty subjects with unilateral, chronic ankle instability (age = 19.8 +/- 1.4 years, height = 176.8 +/- 4.5 cm, mass = 82.9 +/- 21.2 kg) and 20 uninjured subjects matched by sex, sport, and position (age = 20.2 +/- 1.4 years, height = 178.7 +/- 4.1 cm, mass = 82.7 +/- 19.9 kg). MEASUREMENTS: We measured the reach distances in centimeters (cm) and averaged 3 reaches in each of the 8 directions while the subjects stood on each leg for data analysis. RESULTS: The group with chronic ankle instability demonstrated significantly decreased reach while standing on the injured limb compared with the matched limb of the uninjured group (78.6 cm versus 82.8 cm). Additionally, subjects with chronic ankle instability reached significantly less when standing on their injured limbs as compared with their uninjured limbs (78.6 cm versus 81.2 cm). CONCLUSIONS: The SEBTs appear to be an effective means for determining reach deficits both between and within subjects with unilateral chronic ankle instability.

Figure 1

A subject performing the posteromedial-reach component of the Star Excursion Balance Tests.

Figure 2

The 8 directions of the Star Excursion Balance Tests are based on the stance limb.

Figure 3

Significant differences (P < .05) were found between the injured- and uninjured-limb reaches of the chronic ankle instability (CAI) group (#) and the injured-limb reaches of the CAI and the matched side of the control group (*).

Figure 4

The main effect for direction was significant (P < .05), indicating significant differences among the various directions when the data from both groups and both sides were pooled. Reaches in the lateral direction were significantly shorter than reaches in the other 7 directions (*), and reaches in the anterolateral direction were significantly less than all directions except lateral (#). Additionally, posterior and posteromedial reaches were significantly longer than reaches in the anterior, anteromedial, and posterolateral directions (;p0). A indicates anterior; AM, anteromedial; M, medial; PM, posteromedial; P, posterior; PL, posterolateral; L, lateral; and AL, anterolateral.