title: Muscle damage and repeated bout effect following blood flow restricted exercise.
abstract: OBJECTIVE
  Blood-flow restricted resistance exercise training (BFRE) is suggested to be effective in rehabilitation training, but more knowledge is required about its potential muscle damaging effects. Therefore, we investigated muscle-damaging effects of BFRE performed to failure and possible protective effects of previous bouts of BFRE or maximal eccentric exercise (ECC).
  
  
  METHODS
  Seventeen healthy young men were allocated into two groups completing two exercise bouts separated by 14 days. One group performed BFRE in both exercise bouts (BB). The other group performed ECC in the first and BFRE in the second bout. BFRE was performed to failure. Indicators of muscle damage were evaluated before and after exercise.
  
  
  RESULTS
  The first bout in the BB group led to decrements in maximum isometric torque, and increases in muscle soreness, muscle water retention, and serum muscle protein concentrations after exercise. These changes were comparable in magnitude and time course to what was observed after first bout ECC. An attenuated response was observed in the repeated exercise bout in both groups.
  
  
  CONCLUSIONS
  We conclude that unaccustomed single-bout BFRE performed to failure induces significant muscle damage. Additionally, both ECC and BFRE can precondition against muscle damage induced by a subsequent bout of BFRE.
authors.affiliation: Section of Sport Science, Department of Public Health, Aarhus University, Dalgas Avenue 4, 8000, Århus, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Sieljacks
authors.affiliation: Section of Sport Science, Department of Public Health, Aarhus University, Dalgas Avenue 4, 8000, Århus, Denmark.
authors.forename: Andreas
authors.initials: A
authors.lastname: Matzon
authors.affiliation: Department of Food and Nutrition and Sport Science, Center for Health and Performance, University of Gothenburg, Göteborg, Sweden.|Lundberg Laboratory for Orthopaedic Research, Department of Orthopedics, The Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden.
authors.forename: Mathias
authors.initials: M
authors.lastname: Wernbom
authors.affiliation: Department of Clinical Medicine, MR-Research Centre, Aarhus University Hospital, Århus, Denmark.
authors.forename: Steffen
authors.initials: S
authors.lastname: Ringgaard
authors.affiliation: Section of Sport Science, Department of Public Health, Aarhus University, Dalgas Avenue 4, 8000, Århus, Denmark.
authors.forename: Kristian
authors.initials: K
authors.lastname: Vissing
authors.affiliation: Section of Sport Science, Department of Public Health, Aarhus University, Dalgas Avenue 4, 8000, Århus, Denmark. ko@idraet.au.dk.
authors.forename: Kristian
authors.initials: K
authors.lastname: Overgaard
mesh_terms: D006801:Humans; D008297:Male; D009124:Muscle Proteins / Q000097:blood; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000502:physiology; D063806:Myalgia / Q000209:etiology* / Q000503:physiopathology; D012039:Regional Blood Flow; D055070:Resistance Training / Q000009:adverse effects* / Q000379:methods; D019415:Torque; D055815:Young Adult
chemical_list: D009124:Muscle Proteins
keywords: Blood flow occlusion; Eccentric resistance training; Muscle wasting; Preconditioning; Repeated bout effect