Test Properties of Lower Quarter Y-Balance Test: Effect of Verbal Instructions and Focus Techniques

This study is a prospective cross-sectional research. A total of 52 healthy individuals participated in this study. The test protocols were compeleted in two sessions for each participant. In the first session, participants whose eligibility for the study was determined, were recorded demographic data including age, height, body weight, body mass index, lower extremity dominance, and leg length. Subsequently, the Lower Quarter Y Balance Test (LQYBT) was conducted using three different focus instructions: (1) standardized instruction, (2) internal focus instruction, (3) external focus instruction. Each focus instruction was sequentially applied three times in each direction. The three different instructions were randomized and performed in a different sequence for each participant. In second session, to assess the test-retest reliability of different focus instructions during test, the LQYBT was repeated under the same conditions three days later, by the same researcher. To ensure normalization, the average distances measured in the anterior, posteromedial, and posterolateral directions were obtained for each command, and the results were divided by the length of the leg and multiplied by 100. The total score for the dominant side in the LQYBT was determined by aggregating the average reach distance across three directions, dividing it by three times the length of the leg, and then multiplying by 100.