title: Biochemical responses to level-1 yo-yo intermittent recovery test in young tunisian football players.
abstract: OBJECTIVE
  The aim of this work was to investigate the metabolic and muscle damage responses after the level-1 Yo-Yo intermittent recovery test (YYIRT) in young football players.
  
  
  METHODS
  Fifteen male football players (17.42 ± 0.2 yrs, 69.91 ± 4.4 kg, 178.64 ± 3.8 cm; mean ± SD) participated in this study. Fasting blood samples for various biochemical parameters (i.e. lactate (Lac), glucose (GLC), triglycerides (Tri), creatine kinase (CK), uric acid (UA)) collected from a forearm vein after 5-min of seated rest and 3-min after the test. Moreover, rating of perceived exertion (RPE) and maximal heart rate during and after the YYIRT were recorded.
  
  
  RESULTS
  Mean levels of the selected biochemical markers were raised after the YYIRT exercise (P<0.001 for the other markers). Moreover, lipid parameters increased significantly after the test (P<0.01 for Tri and P<0.001 for HDL).
  
  
  CONCLUSIONS
  These findings confirm the higher metabolic demand of aerobic as well as anaerobic metabolism and reflect a significant mobilization of purine cycle during the YYIRT. The increase of muscle damage markers also reflects the higher anaerobic solicitation. From these findings, we can conclude the importance of aerobic and anaerobic metabolism during soccer-specific endurance performance (i.e. YYIRT, soccer match).
authors.affiliation: Research Laboratory "Sport Performance Optimisation", National Center of Medicine and Science in Sport, Tunisia.
authors.forename: Omar
authors.initials: O
authors.lastname: Hammouda
authors.forename: Hamdi
authors.initials: H
authors.lastname: Chtourou
authors.forename: Anis
authors.initials: A
authors.lastname: Chaouachi
authors.forename: Henda
authors.initials: H
authors.lastname: Chahed
authors.forename: Nidhal
authors.initials: N
authors.lastname: Zarrouk
authors.forename: Abdelhedi
authors.initials: A
authors.lastname: Miled
authors.forename: Karim
authors.initials: K
authors.lastname: Chamari
authors.forename: Nizar
authors.initials: N
authors.lastname: Souissi
keywords: Intermittent Recovery Test; Lactate; Lipid Profile; Metabolic Responses