Characteristics of high-level youth soccer players: variation by playing position.

The present study aimed to investigate positional differences in 744 high-level soccer players, aged 8 to 18 years. Players were assigned to six age groups (U9-U19) and divided into four playing positions (goalkeeper (GK), defender (DEF), midfielder (MF) and attacker (ATT)). MANOVA and effect sizes were used to examine anthropometrical and functional characteristics between all positions in all age groups. The main findings of the study were that GKs and DEFs were the tallest and heaviest compared with MFs and ATTs in all age groups. Further, between U9-U15, no significant differences in functional characteristics were found, except for dribbling skill, which MFs performed the best. In the U17-U19 age groups, ATTs seemed to be the most explosive (with GKs), the fastest and the more agile field players. These results suggest that inherent physical capacities (i.e., speed, power, agility) might select players in or reject players from an attacking position, which is still possible from U15-U17. Apparently, players with excellent dribbling skills at younger age are more likely to be selected to play as a MF, although, one might conclude that the typical physical characteristics for different positions at senior level are not yet fully developed among young soccer players between 8 and 14 years.