The speed dynamics of different sprint and acceleration exercises applied during football training

Sprinting actions are related to decisive moments of the match and impose severe fatigue levels on football players, and are often preceded by lower intensity running patterns or walking on the field. This study aimed to compare the effects of different exercise drills on speed and acceleration dynamics. Forty Under-19 and Under-23 soccer players participated in different sprint drill conditions, quantifying their distance covered in various speed intensities covering high-speed running and sprinting patterns and their peak acceleration. The speed drills were compared across different conditions: LS30m (30 m Linear Sprint), LS40m (40 m Linear Sprint), 15BR + LS30m (15 m Bounding Run + 30 m Sprint), 15BR + LS40m (15 m Bounding Run + 40 m Sprint), and CS30m (30 m Chasing Sprint). The results of this study showed significant differences regarding maximal acceleration between the lowest value 15BR + LS30m (5.62 ± 0.83 m/s²) and the highest, CS30m (7.09 ± 1.25 m/s²; p = 0.001; d = - 0.88), as well as with LS30m (6.98 ± 1.43 m/s²; p = 0.003; d = - 0.59), LS40m (6.76 ± 1.60 m/s²; p = 0.002; d = - 0.69) drill. Regarding Sprint 3 distance (distance covered > 95% of maximal speed) significant differences were found between the highest, LS40m (2.42 ± 4.82 m) and the lowest 15BR + LS30m (0.0 ± 0.00; p = 0.057; d = - 0.52) as well LS30m (0.90 ± 3.31 m; p = 0.017; d = - 0.37) drill. These results suggest that the capacity to reach peak acceleration is mediated by how the athlete approaches the linear sprint. Moreover, the LS40m was observed to be a drill that successfully exposes the athlete to their peak speed compared to the LS30m and 15BR + 30 m drills. Therefore, it should be considered the use of LS40m drill for training prescriptions for developing speed or hamstring conditioning. Finally, the CS30m drill exposed the athletes to the highest peak acceleration, probably due to the visual stimulus provided by the opponent, which might have elicited higher levels of motivation for the chasing player. Briefly, in the LS40m, athletes cover more distance above 95% of maximum speed, while the CS30m seems to be more effective for achieving higher accelerations.