French academies almost all implement reactivity drills and small-sided games (SSG) the day preceding a match (MD-1). The present study aimed to determine the physical impact of different training durations on MD-1 on the subsequent matchday performance (MD). Eleven elite U19 academy soccer players con-ducted three typical training sessions lasting 45min (TS45), 60min (TS60), and 75min (TS75) on MD-1. Dur-ing TS60, warm-up, reactivity and SSG were 10, 15, and 24min, respectively, plus coaches' feedback or wa-ter breaks. Durations decreased and increased by 25% for TS45 and TS75, respectively. Tests were con-ducted on MD-4 (CONTROL) and MD before the match (TEST). Tests consisted of a counter movement jump (CMJ), 20m sprint, Illinois agility test (IAT), and Hooper questionnaire. CONTROL values were simi-lar over the three experimental conditions. TEST on MD revealed greater CMJ for TS45 (42.7 ± 5.1cm) compared to TS60 (40.5 ± 5.5cm, p=0.032) and TS75 (40.9 ± 5.7cm, p=0.037). 20m time was lower for TS45 (3.07 ± 0.10s, p<0.001) and TS60 (3.13 ± 0.10s, p=0.017) compared to TS75 (3.20 ± 0.10s). IAT time was lower on TS45 (14.82 ± 0.49s) compared to TS60 (15.43 ± 0.29s, p<0.001) and TS75 (15.24 ± 0.33s, p=0.006). Further-more, the Hooper index was lower at TEST for TS45 (7.64 ± 1.50) compared to TS60 (11.00 ± 3.49, p=0.014) and TS75 (9.73 ± 2.41, p=0.045) indicating a better readiness level. We concluded that as training session duration increases, performance decreases on MD. A 45min training session including reactivity and SSG exercises is therefore recommended on MD-1.