AUTHOR=Prioul Valentin , Slawinski Jean , Guersent Steeve , Lopes Philippe , Leprêtre Pierre-Marie TITLE=Effect of two training modalities on sprint performance in young American football players JOURNAL=Frontiers in Sports and Active Living VOLUME=Volume 7 - 2025 YEAR=2025 URL=https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2025.1554055 DOI=10.3389/fspor.2025.1554055 ISSN=2624-9367 ABSTRACT=BackgroundTime to perform 40-yard dash (40-yd) is a performance criterion in American football. Sprinting ability is strongly correlated with maximal values of horizontal power (PHmax), Force (FH0) and Velocity (VH0). While numerous methods for developing sprint speed exist, few studies have focused on the effects of periodizations on the sprinting mechanical variables in young talented American football players.Objectivethis study aimed to compare the effects of block (BP) and undulating (UP) training periodization modalities on 40-yard dash performance.Method27 players from the Young French League of American football (17.1 ± 0.9 y, 179.9 ± 5.5 cm, 81.1 ± 14.9 kg) were randomly assigned in either the BP (n = 15) or UP (n = 12) group. Anthropometric characteristics, 40-yd performance, maximal velocity (Vmax), PHmax, FH0 and VH0 were assessed before and after 10-wk intervention period.ResultsTraining resulted in the 40-yd performance increase of 3.72% (p < 0.001) and significant changes in Vmax (+ = 6.13 ± 5.62%, p < 0.001) and VH0 values (+2.68 ± 4.14%, p = 0.004). BP intervention leaded higher improvements in time to perform 40-yd (4.45 ± 2.06 vs. 3.02 ± 1.93%, p < 0.001) and Vmax (7.30 ± 6.63% vs. 4.54 ± 4.10%, p = 0.002,) compared to UP. No periodization effect was found in changes of VH0 (BP: 3.42 ± 4.31% vs. UP: 1.48 ± 3.88, p = 0.214).ConclusionOur results showed that BP and UP were effective to increase sprint performance. Despite a similar training load, the block periodization of training had better effects on 40-yd performance compared to undulating training periodization in this population of talented young American football players.