Using minimum effort duration can compromise the analysis of acceleration and deceleration demands in football

The aim of this study was to characterise football players' acceleration and deceleration demands regarding duration, initial velocity, and effort magnitude without a minimum effort duration. Forty-two male professional players were monitored daily during four training weeks, using a global position system. Players were divided according to their playing positions as central defenders, fullbacks, central midfielders, wide midfielders, and forwards. Acceleration and deceleration efforts were analysed from the start of the change in velocity until it stopped increasing (acceleration) or decreasing (deceleration). Descriptive statistics were performed for occurrences, initial velocities, and average and peak magnitudes. Comparisons between playing positions were conducted with one-way analysis of variance (ANOVA). The frequency of accelerations and decelerations decreased as the duration increased. The initial deceleration velocity increased with duration, but no changes were seen in the acceleration initial velocity. The average effort's magnitude increased with duration, while the peak magnitudes decreased, showing acceleration and deceleration peaks between 0.5-1.3 and 0.1-0.3 s, respectively. Differences between playing positions occurred between 0.7 and 2.5 s. In conclusion, the measurement of accelerations and decelerations should avoid the use of minimum effort duration since it can modify the real training load of football players.

Automated summary

The aim of this study was to analyze the acceleration and deceleration demands of football players, including duration, initial velocity, and effort magnitude, without minimum effort duration. Male professional players were monitored daily for four weeks using a global position system. The frequency, initial velocities, and average and peak magnitudes of acceleration and deceleration efforts were analyzed. Variations between playing positions were observed, with differences occurring between 0.7 and 2.5 seconds. The study concludes that the measurement of accelerations and decelerations should not be based on a minimum effort duration as it may alter the actual training load of football players.