introducing an activity-based balance index for soccer players: a validity and reliability study

Objectives]the aim of this study was to evaluate the validity and reliability of introducing a new activitybased balance index using a triaxial accelerometer during activity. methods: twenty seven soccer players (age: 14.5 ± 0.4 years old, body mass: 58.3 ± 9.3 kg, height: 172 ± 8 cm) who participated in the national pre-mier league were recruited. the participants were tested for their balance, activity, and skill in four tests: (i) one leg stance; (ii) dynamic y balance; (iii) running; and (iv) dribbling slalom. the acceleration of the body was recorded using an accelerometer during those tests. by processing acceleration data, a new activitybased balance index (abi) was calculated based on the velocity, acceleration, and position index of soccer players. using intraclass correlation coefficients (icc), reliability was calculated. results: reliability was high (icc = 0.87 0.89; 95% ci = 0.77 0.93) in calculating abi for the three activities performed in the tests. a significant positive correlation between abi and both static and dynamic balance scores (r = 0.62, p = 0.002) was observed. furthermore, negative correlation was found significantly between abi and dribbling scores (r = 0.61, p = 0.026) and y balance test (r = 0.6, p = 0.002). conclusions:in conclusion, the introduced abi demonstrates great potential to determine balance and skill scores based on accelerometer-based measures.