Influência de diferentes sistemas táticos sobre a intensidade de esforço e a fadiga de jogadores de futebol da categoria sub-17

The football game is characterized as a high intensity sport with short recovery intervals, thus, parameters of load measurement during the game have been analyzed to evolve the performance of athletes. The objective of this study was to evaluate the influence of different tactical systems on the intensity of effort (IE), power and fatigue in 10 players, with mean age of 16.6 ± 0.5 years. Heart rate (HR) was monitored through cardiac monitors (Firstbeat®) during two simulated games using the tactical systems 1-4-4-2 (S-1) and 1-4-3-3 (S-2). In order to quantify the values of maximum power (Pmax) and minimum power (Pmin), the RAST (Running-based anaerobic sprint test) anaerobic running test was used in three moments: T1- baseline test, T2- ), T3 – post- test (S-2). The EI recorded in the games did not show significant differences when compared to 1-4-4-2 x 1-4-3-3 (HRmax S-1 189.4 ± 8.18 and 193.6 ± 5.13 bpm S-2) (p 0,151). The mean HR recorded in S-1 was 162.6 ± 7.23 and 164.3 ± 9.64 bpm S-2 (p 0,711). The power values did not present significant changes when compared in the three moments (T1, T2, T2). There was a significant increase in the values of the fatigue index between moments T1 and T2 (* p <0.05). The results obtained in this research demonstrate that both tactical systems studied presented similar responses of the HR and were not able to change the values of maximum and minimum power in the players.