Overmoyer & Reiser (2013) Relationships Between Asymmetries in Functional Movements and the Star Excursion Balance Test

Lower-extremity functional asymmetries (LEFAs) have been shown to be related to performance and injury risk. However, consistency of expression between tasks is not well understood. The goal of this investigation was to examine relationships in vertical ground reaction force LEFA during standing, bodyweight squats, countermovement jumps (CMJs), and single-leg drop landings along with those produced in the Star Excursion Balance Test (SEBT). Twenty (9 men, 11 women) healthy, recreationally active young adults (mean ± SD age: 21.9 ± 2.6 years; height: 171 ± 8.8 cm; mass: 67.2 ± 1.9 kg) performed all tests in a single visit. Correlations of asymmetries between tasks as a whole group and in subsets with larger levels of asymmetries in each task were examined. Many significant correlations (p < 0.05) were found in the asymmetries between the functional tasks, between the reach directions of the SEBT, and between the functional tasks and the SEBT, though they were of low to moderate strength (|r| < 0.8) in the whole group. Except for standing, correlations typically improved in the subset analyses. Most noteworthy was the CMJ subset, which demonstrated strong relationships (|r| > 0.8) with asymmetries in the squat and with the SEBT. Correlations between reach directions in the SEBT improved in the subset comparisons but would not be considered strong. The results suggest that asymmetries are more likely to be expressed in multiple tasks as the bilateral difference increases, that intensity of effort plays a key role in the expression of asymmetries during bilateral tasks, tasks most relevant to the sport should be used when assessing athletes, and though not replacing functional tasks, the SEBT may serve an important role in the diagnosis of LEFA.

Coughlan, Fullam, Delahunt, Gissane & Caulfield (2012) A Comparison Between Performance on Selected Directions of the Star Excursion Balance Test and the Y Balance Test

The Star Excursion Balance Test (SEBT) is a widely accepted method of assessing dynamic postural stability. The Y Balance Test (YBT) is a commercially available device for measuring balance that uses 3 (anterior, posteromedial, and posterolateral) of the 8 SEBT directions and has been advocated as a method for assessing dynamic balance. To date, no studies have compared reach performance in these tests in a healthy population.
Objective To determine whether any differences exist between reach distance performance for the anterior, posteromedial, and posterolateral directions of the SEBT and the YBT.
Design Descriptive laboratory study.
Setting University motion analysis laboratory.
Patients or Other Participants A total of 20 healthy active male participants (age = 22.50 ± 3.05 years, height = 1.78 ± 0.82 m, weight = 79.48 ± 11.32 kg, body mass index = 24.96 ± 2.56 kg/m2).
Interventions Participants carried out 3 trials in each reach direction on each leg on the SEBT and the YBT a minimum of 1 week apart.
Main Outcome Measure(s) The means of the 3 trials in each direction on each leg on both tests were calculated. Data were collected after 4 practice trials in each direction. Paired t tests and Bland-Altman plots were used to compare reach distances between the SEBT and the YBT.
Results Participants reached farther in the anterior direction on the SEBT than on the YBT. No differences were observed in the posteromedial and posterolateral directions.
Conclusions Differing postural-control strategies may be used to complete these tasks. This finding has implications for the implementation and interpretation of these dynamic balance tests.

Tristan Chai