Functional performance and interlimb asymmetries of young football players during single-leg jump tests

146 young, uninjured male football players (age 14.2 ± 2.3) from a 3rd division professional German team, categorized into age groups U11-U19. Inclusion criteria: active involvement in training practices/games without restriction, aged 10–19 years. Exclusion criteria: lower limbs major injury (with more than 7 days of absence) or surgery in the previous 12 months.

Single-leg jump tests (countermovement jump, jump for distance, side hop, and speedy jump tests)

Dominant versus non-dominant leg, and comparisons across age groups (U11-U19)

Age-specific mean values of single-leg functional performance and limb symmetry index (LSI)