Positional differences in the cardiorespiratory, autonomic, and somatic profiles of professional soccer players

In order to optimize training in soccer, knowledge about the specific position fitness demands and characteristics is required. Objective: The aim of the study was to determine whether there are position specific differences in somatic, cardiorespiratory and autonomic cardiac profiles of professional senior Czech soccer players. Methods: All players (N = 120) were divided into six groups according to field positions: goalkeeper (GK; n = 11), external defenders (ED; n = 15), central defenders (CD; n = 18), external midfielders (EM; n = 18), central midfielders (CM; n = 24) and forwards (F; n = 34). Players underwent anthropometrical and heart rate variability (HRV) assessment, and a maximal incremental running test in order to obtain maximal oxygen uptake (VO ₂max) and heart rate. HRV variables were transformed using the natural logarithm (Ln). Results: GK and CD were significantly (p = .005) heavier than ED, EM, CM, and F; while F were significantly (p = .026) heavier than CM and EM. GK and CD were significantly (p = .008) taller than ED, EM, CM, F; and EM were significantly (p = .041) shorter than CM and F. The only significant (p = .043) difference in percentage of body fat was observed in CD compared with CM. A significantly (p = .021) lower VO ₂max was observed for GK compared with ED, CD, EM, CM, and F. Supine HRV was significantly (p = .039) lower for Ln LF/HF in GK compared with F. Standing HRV was significantly (p = .03) lower for Ln LF in CD compared with both ED and F, significantly (p = .028) higher for Ln LF/HF in ED compared with CD and EM. Conclusions: In soccer, specific positions are associated with different height, body mass and aerobic capacity. A lower VO ₂max and vagal activity in GK compared with other playing positions may not be considered as disadvantage for performance in this specific playing position.