Influence of games system on the physical and physiological demands in young soccer 7 (U12)

The aim of this article was to describe activity patterns and heart rate frequency of young players in soccer 7 through GPS technology and to determine whether differences exist according to the game system utilized during matches. 42 players were investigated (11.2±0.7 years; 146±0.1 cm; 42±9.4 kg; 19.6±3.2 body mass). The players participated in fifteen matches using the 1-3-3 system and another fifteen using the 1-2-3-1 system, each match lasting twenty five minutes. Maximum heart rate (HRmax) and average heart rate(HRavg) were registered (absolute and relative) and so were the following physical variables: total distance, distance covered in different speed ranges, sprint characteristics, number of accelerations/decelerations during the different ranges of intensity and the indicators of global load (work-rest ratio, maximum speed and Effindex). In both of the game play systems studied (1-3-3 and 1-2-3-1) similar results were obtained in all the physical variables. However the time that the players spent over 90% of HRmax (6.86% vs. 3.17%) were significantly (p=0.015) higher in the 1-3-3 system than in the 1-2-3-1 system. It is also worth noting that the distance covered in the last 5 minutes of the game was significantly (p