Reliability and number of trials of Y Balance Test in adolescent athletes.

Background: The Star Excursion Balance Test (SEBT) is commonly used to evaluate dynamic equilibrium. The Y Balance Test (Y-BT) is a shortened version of the SEBT where a Y- Balance Kit is commonly used. To date, research concerning the protocol and reliability of the SEBT and Y-BT has been conducted only for adults.

Objectives: The aim of the study was to assess the protocol (the necessary number of trials to stabilize the results) and reliability of the Y-BT in adolescent athletes.

Design: One-way repeated-measures analysis of variance (ANOVA) and reliability study.

Method: The sample of 38 athletes (mean age: 15.6 years) was selected from a football club. A Y-Balance test kit was applied for the evaluation of dynamic balance. The analysis used the values normalized to the relative length of the lower limbs.

Results: After six attempts, three consecutive ones achieved stability for all directions and both extremities (p > 0.05). The intraclass correlation coefficient (ICC), standard error of measurement and minimal detectable change values for the three attempts ranged from 0.57 to 0.82, from 3 to less than 6% and from 7.68 to 13.7%, respectively.

Conclusions: In the study of adolescent dynamic equilibrium using the Y-BT, it is recommended to perform nine attempts (including six trial attempts and three measurements). In order to increase reliability it is recommended that the average of the three measured attempts is analysed.