title: Biochemical, physical and tactical analysis of a simulated game in young soccer players.
abstract: BACKGROUND
  The objectives of this study were to describe and compare the displacement patterns and the tactical performance of the players in the first to the second game time and verify possible associations between indirect markers of muscle damage with displacement patterns in a simulated game played by young soccer players.
  
  
  METHODS
  Eighteen young soccer players were submitted to a simulated game and two blood collections, one before and another 30 minutes post-game to analyze the behavior of creatine kinase and lactate dehydrogenase enzymes. The patterns of displacement and tactics variables were obtained through functions developed in MATLAB environment (MathWorks, Inc., Natick, MA, USA).
  
  
  RESULTS
  It is observed a significant increase in average speed (P=0.05), number of sprints (P<0.001), the percentage the total distance covered at high intensity (P<0.001) and tactical variables (team surface area: P=0.002; spreading: P=0.001) in the second period of the simulated game. In addition, there was significant reduction in the percentage of the total distance at low intensity (P≤0.05) in the second period, and there was a strong association between the percentage of change delta of creatine kinase and lactate dehydrogenase with the displacement patterns in the simulated game.
  
  
  CONCLUSIONS
  The results show that indirect markers of muscle damage have great association with displacement patterns in game performed in training conditions for young soccer players, evidencing a need for reflection on the post-training recovery sessions strategies, contributing to better planning of sessions throughout the macrocycle.
authors.affiliation: Faculty of Sports Science, Porto University, Porto, Portugal.|Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Rodrigo L
authors.initials: RL
authors.lastname: Aquino
authors.affiliation: Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Luiz G
authors.initials: LG
authors.lastname: Gonçalves
authors.affiliation: Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Luiz H
authors.initials: LH
authors.lastname: Vieira
authors.affiliation: Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Lucas P
authors.initials: LP
authors.lastname: Oliveira
authors.affiliation: Faculty of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Guilherme F
authors.initials: GF
authors.lastname: Alves
authors.affiliation: School of Physical Education and Sport of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Paulo R
authors.initials: PR
authors.lastname: Santiago
authors.affiliation: School of Physical Education and Sport of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil - enrico@usp.br.
authors.forename: Enrico F
authors.initials: EF
authors.lastname: Puggina
mesh_terms: D000293:Adolescent; D054874:Athletic Performance / Q000502:physiology; D015415:Biomarkers / Q000097:blood*; D001938:Brazil; D003402:Creatine Kinase / Q000097:blood; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries* / Q000473:pathology / Q000502:physiology*; D012916:Soccer / Q000502:physiology*
chemical_list: D015415:Biomarkers; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase