Effects of Taekwondo Match-Simulated Fatigue on Balance Performance in Female Athletes

The Mean Overall Stability Index Score is the arithmetic mean of Overall Stability Index values automatically calculated by the Biodex system at the end of each 20-second single-leg stance trial. This index is a unitless score representing the standard deviation of platform tilt about both the anteroposterior and mediolateral axes combined; it reflects composite postural sway during the trial. Each participant completed the trial barefoot on her dominant lower extremity, under two within-subject conditions: (i) dynamic balance (eyes-open stance with the Biodex platform stability set to level 5), and (ii) static balance (eyes-closed stance with the platform locked at a static level). The index is a unitless score representing the standard deviation of platform tilt about the corresponding axis; the theoretical minimum score is 0, which represents perfect postural stability. There is no fixed theoretical upper limit of these indices. Higher scores indicate poorer balance performance.

The Mean Mediolateral Stability Index Score is the arithmetic mean of Mediolateral Stability Index values automatically calculated by the Biodex Balance System at the end of each 20-second single-leg stance trial. This index is a unitless score representing the standard deviation of platform tilt about the frontal axis only; it reflects mediolateral sway and is associated with hip-abductor-driven postural control. Each participant will complete the trial barefoot on her dominant lower extremity (the foot preferred for kicking a ball) under two within-subject conditions: (i) dynamic balance (eyes-open stance with the Biodex platform stability set to level 5), and (ii) static balance (eyes-closed stance with the platform locked at a static level). Theoretically, this index has a minimum value of 0, which represents perfect postural stability; there is no fixed theoretical upper limit. Higher scores indicate poorer balance performance.

The Mean Anterior-Posterior Stability Index Score is the arithmetic mean of Anterior-Posterior Stability Index values automatically calculated by the Biodex system at the end of each 20-second single-leg stance trial. This index is a unitless score representing the standard deviation of platform tilt about the sagittal axis only; it reflects anteroposterior sway and is associated with the ankle strategy of postural control. Each participant will complete the trial barefoot on her dominant lower extremity (the foot preferred for kicking a ball) under two within-subject conditions: (i) dynamic balance (eyes-open stance with the Biodex platform stability set to level 5), and (ii) static balance (eyes-closed stance with the platform locked at a static level). Theoretically, this index has a minimum value of 0, which represents perfect postural stability; there is no fixed theoretical upper limit. Higher scores indicate poorer balance performance.

The mean chronological age of participants at the time of enrollment will be reported in years. Age will be derived from each participant's official identification date of birth and the calendar date of the first balance testing session. It will be used solely as a descriptive baseline demographic variable.

Mean Body Mass Index is the arithmetic mean of participant-level BMI values aggregated from body mass (kg) and height (m) according to the standard formula BMI = body mass (kg) / height² (m²). Body mass will be measured in kilograms and standing height in centimeters by a single trained experimenter during the enrollment session. Each participant-level BMI is therefore a single aggregated value derived from two distinct unit-of-measure measurements; height (centimeters) and body mass (kilograms) are not reported separately. It will be used solely as a descriptive baseline demographic variable.