title: Sex differences in acute translational repressor 4E-BP1 activity and sprint performance in response to repeated-sprint exercise in team sport athletes.
abstract: OBJECTIVE
  The physiological requirements underlying soccer-specific exercise are incomplete and sex-based comparisons are sparse. The aim of this study was to determine the effects of a repeated-sprint protocol on the translational repressor 4E-BP1 and sprint performance in male and female soccer players.
  
  
  METHODS
  Cross-over design involving eight female and seven male university soccer players.
  
  
  METHODS
  Participants performed four bouts of 6 × 30-m maximal sprints spread equally over 40 min. Heart rate, sprint time and sprint decrement were measured for each sprint and during the course of each bout. Venous blood samples and muscle biopsies from the vastus lateralis were taken at rest, at 15 min and 2h post-exercise.
  
  
  RESULTS
  While males maintained a faster mean sprint time for each bout (P < 0.05) females exhibited a greater decrement in sprint performance for each bout (P < 0.05), indicating a superior maintenance of sprint performance in males, with no sex differences for heart rate or lactate. Muscle analyses revealed sex differences in resting total (P < 0.05) and phosphorylated (P < 0.05) 4E-BP1 Thr37/46, and 15 min post-exercise the 4E-BP1 Thr37/46 ratio decreased below resting levels in males only (P < 0.05), indicative of a decreased translation initiation following repeated sprints.
  
  
  CONCLUSIONS
  We show that females have a larger sprint decrement indicating that males have a superior ability to recover sprint performance. Sex differences in resting 4E-BP1 Thr37/46 suggest diversity in the training-induced phenotype of the muscle of males and females competing in equivalent levels of team-sport competition.
authors.affiliation: School of Sport and Exercise, Massey University, Palmerston North, New Zealand; Sport Performance Research Institute New Zealand (SPRINZ), School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.
authors.forename: Jessica R
authors.initials: JR
authors.lastname: Dent
authors.affiliation: School of Sport and Exercise, Massey University, Palmerston North, New Zealand; Department of Sport and Exercise Science, University of Auckland, Auckland, New Zealand.
authors.forename: Johann A
authors.initials: JA
authors.lastname: Edge
authors.affiliation: Sports and Health Sciences, Dala Sports Academy, Dalarna University, Falun, Sweden.
authors.forename: Emma
authors.initials: E
authors.lastname: Hawke
authors.affiliation: AgResearch Ltd., Ruakura Research Centre, Hamilton, New Zealand.
authors.forename: Christopher
authors.initials: C
authors.lastname: McMahon
authors.affiliation: School of Sport and Exercise, Massey University, Palmerston North, New Zealand. Electronic address: T.Mundel@massey.ac.nz.
authors.forename: Toby
authors.initials: T
authors.lastname: Mündel
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000097:blood* / Q000378:metabolism; D000293:Adolescent; D054874:Athletic Performance / Q000502:physiology*; D001706:Biopsy; D018797:Cell Cycle Proteins; D018592:Cross-Over Studies; D005260:Female; D006339:Heart Rate; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010750:Phosphoproteins / Q000097:blood* / Q000378:metabolism; D010766:Phosphorylation; D052097:Quadriceps Muscle / Q000473:pathology; D020127:Recovery of Function; D012097:Repressor Proteins / Q000378:metabolism; D012420:Running / Q000502:physiology*; D012737:Sex Factors; D012916:Soccer / Q000502:physiology*; D055815:Young Adult
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; C087000:EIF4EBP1 protein, human; D010750:Phosphoproteins; D012097:Repressor Proteins; D019344:Lactic Acid
keywords: Cell signalling; Performance; Sex differences; Soccer; Sprinting