Physical and anthropometric changes during pre- and in-season in professional soccer players

Background: The purpose of this study was to examine the changes in anthropometric and physical fitness characteristics in professional soccer players at the beginning of the season, after preseason camp and during in-season. Methods: Seventeen players were evaluated on three different periods (June: T0, August: T1 and December: T2). Each evaluation consisted of anthropometric measurements (body mass, height, and body fat) and physical fitness tests (counter movement jump [CMJ], counter movement jump with arm (CMJA), 10-m sprint, 30-m sprint and maximal aerobic speed [MAS]). Results: Comparatively with T0, all physical performances achieved in T1 were significantly improved (MAS: P<0.01, 10-m sprint: P<0.05, 30-m sprint: P<0.05, CMJ: P<0.01, and CMJA: P<0.05). The decrease in training load during in-season is associated by significant decrement in MAS (P<0.05) and preserved performances in 10 (P=0.85) and 30-m sprint (P=0.99), CMJ (P=0.34) and CMJA (P=0.87) completed in T2 comparatively with T1. Physical fitness performances achieved in T2 remain higher than that obtained in T0 (MAS: P<0.01, 10-m sprint: P<0.01, 30-m sprint: P<0.05 and CMJ: P<0.05) and remain similar for CMJA (P=0.13). No significant changes were observed in anthropometric measurements throughout the study. Conclusions: The main finding of this study was that a greater training load accomplished during preseason could lead to an improvement in the physical fitness during in-season in professional soccer players. We suggest that this higher training load meets the needed required for the professional soccer although the training loads are declined during in-season.