title: Discrepancy between exercise performance, body composition, and sex steroid response after a six-week detraining period in professional soccer players.
abstract: OBJECTIVE
  The aim of this study was to examine the effects of a six-week off-season detraining period on exercise performance, body composition, and on circulating sex steroid levels in soccer players.
  
  
  METHODS
  Fifty-five professional male soccer players, members of two Greek Superleague Teams (Team A, n = 23; Team B, n = 22), participated in the study. The first two weeks of the detraining period the players abstained from any physical activity. The following four weeks, players performed low-intensity (50%-60% of VO2max) aerobic running of 20 to 30 minutes duration three times per week. Exercise performance testing, anthropometry, and blood sampling were performed before and after the six-week experimental period.
  
  
  RESULTS
  Our data showed that in both teams A and B the six-week detraining period resulted in significant reductions in maximal oxygen consumption (60,31±2,52 vs 57,67±2,54; p<0.001, and 60,47±4,13 vs 58,30±3,88; p<0.001 respectively), squat-jump (39,70±3,32 vs 37,30±3,08; p<0.001, and 41,05±3,34 vs 38,18±3,03; p<0.001 respectively), and countermovement-jump (41,04±3,99 vs 39,13±3,26; p<0.001 and 42,82±3,60 vs 40,09±2,79; p<0.001 respectively), and significant increases in 10-meters sprint (1,74±0,063 vs 1,79±0,064; p<0.001, and 1,73±0,065 vs 1,78±0,072; p<0.001 respectively), 20-meters sprint (3,02±0,05 vs 3,06±0,06; p<0.001, and 3,01±0,066 vs 3,06±0,063; p<0.001 respectively), body fat percentage (Team A; p<0.001, Team B; p<0.001), and body weight (Team A; p<0.001, Team B; p<0.001). Neither team displayed any significant changes in the resting concentrations of total-testosterone, free-testosterone, dehydroepiandrosterone-sulfate, Δ4-androstenedione, estradiol, luteinizing hormone, follicle-stimulating hormone, and prolactin. Furthermore, sex steroids levels did not correlate with exercise performance parameters.
  
  
  CONCLUSIONS
  Our results suggest that the six-week detraining period resulted in a rapid loss of exercise performance adaptations and optimal body composition status, but did not affect sex steroid resting levels. The insignificant changes in sex steroid concentration indicate that these hormones were a non-contributing parameter for the observed negative effects of detraining on exercise performance and body composition.
authors.affiliation: Department of Clinical Chemistry-Biochemistry, University of Crete, School of Medicine, Heraklion, Greece.
authors.forename: Nikolaos E
authors.initials: NE
authors.lastname: Koundourakis
authors.affiliation: Department of Hematology Laboratory, University Hospital, Heraklion, Greece.
authors.forename: Nikolaos E
authors.initials: NE
authors.lastname: Androulakis
authors.affiliation: Departments of Clinical Chemistry-Biochemistry, University of Crete, School of Medicine, and University Hospital, Heraklion, Greece.
authors.forename: Niki
authors.initials: N
authors.lastname: Malliaraki
authors.affiliation: Department of Clinical Chemistry-Biochemistry, University of Crete, School of Medicine, Heraklion, Greece.
authors.forename: Christos
authors.initials: C
authors.lastname: Tsatsanis
authors.affiliation: Department of Clinical Chemistry-Biochemistry, University of Crete, School of Medicine, Heraklion, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Venihaki
authors.affiliation: Departments of Clinical Chemistry-Biochemistry, University of Crete, School of Medicine, and University Hospital, Heraklion, Greece.
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Margioris
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D000328:Adult; D056352:Athletes; D001823:Body Composition; D001835:Body Weight; D015444:Exercise / Q000502:physiology*; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006801:Humans; D008297:Male; D009068:Movement; D010101:Oxygen Consumption; D012916:Soccer; D055815:Young Adult
chemical_list: D012739:Gonadal Steroid Hormones