Changes in Single Leg Countermovement Jump Force-Time Characteristics Pre, Post and 2 Days Postmatch in Elite Girls' Youth Soccer.

Abstract: Fahey, JT, Comfort, P, and Ripley, NJ. Changes in single leg countermovement jump force-time characteristics pre, post, and 2 days postmatch in elite girls' youth soccer. J Strength Cond Res 39(6): e788-e797, 2025-This study was designed to assess changes in force-time characteristics during the single leg countermovement jump pre- ( n = 122), immediately postmatch ( n = 121), and 2 days postmatch (MD +2, n = 105) in elite girls' soccer players ( n = 32, 13.9 ± 1.1 years, 163.4 ± 5.2 cm, 53.6 ± 8.2 kg), after 8 competitive matches, using force plates. Significant main effects were found for all variables ( p < 0.05). Trivial to small, yet significant increases in jump height (JH) and relative mean braking and propulsive forces were observed postmatch for both limbs. Trivial to small, yet significant increases in JH and jump momentum were observed MD +2 for both limbs. Trivial to small, yet significant increases were observed for body mass and time to take-off were observed MD +2 compared with postmatch for both limbs. Playing time was not associated with percentage change in force-time characteristics ( r ≤ 0.20). Competitive matches in elite girls' soccer seem to provide an insufficient stimulus to acute fatigue. Force-time characteristics were improved at postmatch and MD +2 when compared with prematch. This provides useful information for sports coaches and strength and conditioning coaches when prescribing training for progressive overload. Because girls' soccer players experience increased demands with age and competition levels, strength and conditioning coaches should consider the removal of second-day recovery sessions and include strength and high-intensity training on MD +2 to better prepare players to cope with the increasing demands and to reduce injury risk, which remains substantially higher than that for boys.