Test Re-Test Reliability of Countermovement Jump, Single Leg Countermovement Jump, and Countermovement Rebound Jump Force Plate Metrics in Female Football Players

Female football is growing exponentially. Assessing changes in neuromuscular function enables injury risk profiling using single and multiple countermovement jumps (CMJ) in female footballers who are at greater injury risk. Single leg CMJ (SLCMJ) is sensitive to detect such changes, but test-retest reliability is unknown. The aim of this study was to examine test-retest reliability of phase-specific metrics during CMJ, SLCMJ and countermovement rebound (CMJ-R) in female youth footballers. Twenty-six elite female footballers (15.4±1.6 years, 59.2±2.4 kg, 165.8±4.8 cm) performed three, arms akimbo, CMJ, SLCMJ and CMJ-R trials on two sessions seven days apart, using force plates and associated software. System weight, jump momentum and average braking force had good-excellent reliability. CMJ demonstrated greater reliability followed by CMJ-R, dominant limb (DL: preferred kicking limb) SLCMJ and non-dominant limb (NDL) SLCMJ. Jump height had good-excellent reliability for CMJ and CMJ-R. SLCMJ absolute reliability (upper 95 confidence interval [CI] coefficient of variation) was moderate for both limbs. Relative reliability (lower 95 CI interclass correlation coefficient) was good for DL, but poor for NDL. Considering increased injury risk in female athletes, selecting reliable metrics facilitate accurate neuromuscular function assessment for injury risk profiling. This study describes phase-specific test-retest reliability in female youth footballers.