Joint flexibility, bilateral asymmetries in flexibility, and bilateral asymmetries in performance of the Y Balance Test have been associated with injuries. However, relationships among these attributes are unclear. The goal of this investigation was to examine how flexibility and flexibility asymmetries relate to the Y Balance Test. Twenty healthy active young adults (9 men and 11 women; mean ± SD: age = 21.9 ± 2.6 years; height = 171 ± 8.8 cm; mass = 67.2 ± 1.9 kg) performed 9 different lower extremity active range of motion (AROM) tests and the Y Balance Test in a single visit. Significant correlations (p ≤ 0.05) existed between bilateral average AROM measures and bilateral average Y Balance Test scores at the ankle and hip. Specifically, ankle dorsiflexion AROM at 0° knee flexion significantly correlated with Anterior, Posterolateral, and Composite directional scores of the Y Balance Test (r = 0.497-0.736). Significant correlations in ankle dorsiflexion AROM at 90° knee flexion also existed with Anterior, Posterolateral, Posteromedial, and Composite directional scores (r = 0.472-0.795). Hip flexion AROM was significantly correlated with Posterolateral, Posteromedial, and Composite directional scores (r = 0.457-0.583). Significant correlations between asymmetries in AROM and asymmetries in the Y Balance Test existed only in ankle plantarflexion with Anterior, Posterolateral, and Composite directional scores of the Y Balance Test (r = 0.520-0.636). Results suggest that when used with recreationally active healthy adults, the Y Balance Test may help identify lower-extremity flexibility deficits and flexibility asymmetries in the ankle and hip regions but may need to be used in conjunction with additional tests to understand a broader picture of functional movement and injury risk.

RELATIONSHIPS BETWEEN ASYMMETRIES IN FUNCTIONAL MOVEMENTS AND THE STAR EXCURSION BALANCE TESTLower extremity functional asymmetries (LEFA) as well as the Star Excursion Balance Test (SEBT) have been used to screen for injury risk and assess post-injury function. Both have also been shown to relate to physical performance. However, the relationships between LEFA, observed during different tasks, are not well understood, nor are the relationships between LEFA and side-to-side asymmetries in SEBT scores.As a result, it is difficult to determine which methods are most appropriate to assess detrimental asymmetries and whether they might be interchangeable. PURPOSE: The goal of this investigation was to examine the correlation in LEFA using measurement of vertical ground reaction forces (GRFv) during quiet standing, body weight squats, maximal effort counter-movement jumps (CMJ) and single-leg drop landings from a 30.5 cm platform (SLDL). Another goal was to investigate bilateral asymmetries in the SEBT anterior (Ant), posteromedial (PostMed) and posterolateral (PostLat) excursion directions, in both the correlations to each other and the correlations to the four functional movement tasks listed above. METHODS: Twenty recreationally active men (n=9) and women (n=11) (mean ± SD age: 21.9 ± 2.6 yrs; height 171 ± 8.8 cm; mass 67.2 ± 1.9 kg) performed three measured trials of each excursion direction of the SEBT, five 20 second quiet standing trials, five unloaded (body weight) squats, five CMJ and five SLDL on iii each side. Leg length measurements, GRFv data and SEBT scores for each leg were collected. Asymmetry was calculated by subtracting the % load on the preferred kicking leg (KL), or during the SEBT the percent of the bilaterally summed score on the KL, from that of the non-preferred kicking leg (NKL). Results were analyzed using Pearson's correlation and paired t-tests. Eleven subjects were reassessed for repeatability measures. RESULTS:Significant correlations (p<0.05) were found between asymmetries in several of the parameters measured in the LEFA tasks. Standing and average GRFv during CMJ significantly correlated to each other (r= 0.458); average GRFv during squats significantly correlated with standing GRFv (r= -0.452); both maximum and average GRFv during the squat significantly correlated with average and maximum GRFv during CMJ (r= -0.571 to -0.768). Average GRFv to peak in the SLDL significantly related to the squat (r= -0.494 to -0.500) and peak GRFv during the SLDL significantly related to CMJ average GRFv (r= -0.470). Further significance was identified among asymmetries in several SEBT excursion directions, particularly between the Ant versus PostMed (r= 0.406 to 0.564), and Ant versus PostLat (r= 0.470 to 0.570). There was a wide range of significant correlations in regards to combinations of these scores in the SEBT (r= 0.470 to 0.973). And finally, correlations were found to exist between several of the LEFA tasks and SEBT excursion directions. These included squats versus PostMed and Ant...

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