Seasonal Changes in the Acceleration–Speed Profile of Elite Soccer Players: A Longitudinal Study

This study aimed to describe the acceleration–speed (AS) profile of soccer players during competition and to analyse their seasonal changes and inter-player differences. The AS profile values (theoretical maximum acceleration (A0) and speed (S0)) of 14 elite soccer players were studied in 18 matches, which were divided into five season periods. The main findings showed the A0 (6.20 ± 0.51 m/s2) and S0 (9.18 ± 0.58 m/s) average team season values. Significant individual changes (p < 0.05 and effect size (Eta-squared, η2) > 0.5) were confirmed for A0 (Players 4 and 8) and S0 (Players 6, 8 and 11). Additionally, standard deviations (SD±) confirmed small (±0.20–0.60) to moderate (±0.60–1.20) seasonal variations for most players in A0 (SD range: ±0.22 to ±0.69 m/s2) and S0 (SD range: ±0.27 to ±0.90 m/s). SD showed small to moderate inter-player differences for each period for A0 (SD range: ±0.39 to ±0.61 m/s2) and S0 (SD range: ±0.53 to ±0.61 m/s). In summary, coaches are recommended to assess the AS profile to diagnose potential player seasonal changes in sprinting performance, especially for A0, which seems to be more sensitive to variations than S0.