Study Design Case-control study.

Objectives To assess the ability of the Dynamic Leap Balance Test (DLBT) to identify balance deficits in subjects with chronic ankle instability (CAI), and to compare dynamic balance performance between the DLBT and modified Star Excursion Balance Test (mSEBT).

Background Clinicians require functional tests to objectively measure patient outcomes. The mSEBT is commonly used in lower extremity injuries to measure the dynamic control of body movements over an unchanging base of support (BOS). The DLBT is a new dynamic balance task that requires serial changes in BOS with alternating limb support and recovery of dynamic stability.

Methods and Measures Thirty-six young, physically-active adults were divided into two groups: 18 with history of unilateral CAI and 18 healthy. CAI subjects were identified using the Identification of Functional Ankle Instability (IdFAI) questionnaire. Subjects were randomly assigned to complete the mSEBT or DLBT on their CAI (or healthy matched) or contralateral limb on Day 1, and perform the same tasks with the other limb on Day 2.

Results There were no statistically significant differences (p>0.05) among any of the four conditions for normalised composite or reach distance measures (% leg length) with the mSEBT. Statistically significant differences (p<0.001) in DLBT time were found among limbs. The DLBT time for the CAI limb (51.8±4.04 s, 95% CI=51.18, 53.52) was significantly greater than the CAI contralateral limb (44.12±3.60 s, 95% CI=42.52, 45.78) and the healthy matched limb (41.88±3.36 s, 95% CI=40.21, 43.55).

Conclusion The DLBT may be a more discriminate measure of dynamic balance than the mSEBT in CAI subjects. The leaping task in the DLBT involves BOS changes, and dynamic stability reestablishment while requiring greater production and attenuation of forces similar to running, cutting and jumping.