title: Comparison of physical performance among Brazilian elite soccer players of different age-categories.
abstract: BACKGROUND
  The purpose of this study was to compare the physical performance (i.e., strength, power, speed and endurance) between Brazilian elite soccer players from different categories of the same club: professionals (PRO), under-20 (U-20), and under-17 (U-17).
  
  
  METHODS
  Seventy-one soccer players from three categories (PRO=24; U-20=21 and U-17=26) were assessed at the beginning of pre-season. Before the tests, they were familiarized with all experimental procedures. Squat jump (SJ), countermovement jump (CMJ), sprint (10 m/20 m), maximum dynamic strength (1RM), and Yo-Yo intermittent recovery tests level 1 were performed in three non-consecutive sessions.
  
  
  RESULTS
  No significant differences were found between the categories for sprint times. The PRO players presented higher outcomes in the 1RM, SJ, CMJ, and Yo-Yo tests than the U-20 and U-17 players (P≤0.05). No significant differences were found between the U-20 and U-17 players in 1RM, and SJ/CMJ heights. The U-20 presented superior performance than the U-17 in the Yo-Yo test (P≤0.05).
  
  
  CONCLUSIONS
  The findings indicated that PRO performed better than younger players in all assessments, except for the sprint tests. This may have been possible due to the differences in training experience, technical expertise and individual levels of strength/power. However, the absence of differences between the U-20 and U-17 groups highlighted the necessity of developing specific training strategies in order to improve the physical capacities of younger players, throughout the maturation process. Moreover, due to the importance of sprinting in soccer, it is strongly recommended that fitness coaches develop more effective strategies to improve speed ability in professional players.
authors.affiliation: NAR, Nucleus of High Performance in Sport, São Paulo, Brazil - ronaldo.kobal@narsp.com.br.
authors.forename: Ronaldo
authors.initials: R
authors.lastname: Kobal
authors.forename: Irineu
authors.initials: I
authors.lastname: Loturco
authors.forename: Saulo
authors.initials: S
authors.lastname: Gil
authors.forename: Cesar C
authors.initials: CC
authors.lastname: Cal Abad
authors.forename: Rogério
authors.initials: R
authors.lastname: Cuniyochi
authors.forename: Renato
authors.initials: R
authors.lastname: Barroso
authors.forename: Valmor
authors.initials: V
authors.lastname: Tricoli
mesh_terms: D000293:Adolescent; D056352:Athletes; D054874:Athletic Performance / Q000502:physiology*; D001938:Brazil; D015444:Exercise; D005080:Exercise Test; D006801:Humans; D008297:Male; D010809:Physical Fitness; D012420:Running; D012916:Soccer; D055815:Young Adult