Acute effects of the FIFA 11 + kids warm-up program compared with a judo-specific warm-up on explosive and functional performance in youth judo athletes: a randomized crossover study

BACKGROUND: The FIFA 11 + Kids (FIFA 11+) warm-up program is effective for injury prevention and to enhance sports performance, including vertical jump (VJ), sprint, balance, and agility. However, no previous study has examined the acute effects of FIFA 11 + on performance outcomes in youth judo athletes. Therefore, this study aimed to investigate the acute effects of the FIFA 11 + warm-up program on selected physical performance parameters of youth judo athletes compared to the judo-specific warm-up (JSWU). This study employed a randomized, counterbalanced crossover design. METHODS: ; training age: 3.56 ± 1.31 years) completed two warm-up conditions (FIFA 11 + vs. JSWU). The following performance tests were conducted during the test sessions: vertical jump, 5-10 m sprint, bilateral leg strength (LS), back strength (BS), handgrip strength (HS), lower-limb functional strength (single hop for distance (SLHD), triple hop for distance (THD), crossover hop for distance (CHD)), change of direction (CoD), broad jump and overhead medicine ball (OMB) throw. RESULTS: There were significant differences between JSWU and FIFA 11 + conditions for vertical jump (39.44 ± 7.21 vs. 41.88 ± 6.67, p = 0.008, η² = 0.40), anaerobic power (641.45 ± 211.13 vs. 665.69 ± 228.44, p = 0.010, η² = 0.38), and overhead medicine ball throw (375.19 ± 110.72 vs. 410.44 ± 114.95, p = 0.002, η² = 0.50). Significant differences were also observed in SLHD (right and left) and CHD (left), although the effect sizes were moderate to large. CONCLUSIONS: The findings indicate that the FIFA 11 + program produced small acute improvements in selected explosive and unilateral functional performance outcomes (i.e., vertical jump, OMB throw, SLHD, and CHDLeft), while most other variables showed no significant differences compared with the judo-specific warm-up. These findings should be interpreted cautiously despite the large effect sizes, as the magnitude of improvement was practically small. The FIFA 11 + program may be a potential alternative warm-up option, though its practical application should be interpreted with caution. TRIAL REGISTRATION: The randomized controlled trial was retrospectively registered on 03/23/2026 at ClinicalTrials.gov, under the registration number NCT07487558 (https://clinicaltrials.gov/study/NCT07487558).