title: Changes in Serum Free Amino Acids and Muscle Fatigue Experienced during a Half-Ironman Triathlon.
abstract: The aim of this study was to investigate the relationship between changes in serum free amino acids, muscle fatigue and exercise-induced muscle damage during a half-ironman triathlon. Twenty-six experienced triathletes (age = 37.0 ± 6.8 yr; experience = 7.4 ± 3.0 yr) competed in a real half-ironman triathlon in which sector times and total race time were measured by means of chip timing. Before and after the race, a countermovement jump and a maximal isometric force test were performed, and blood samples were withdrawn to measure serum free amino acids concentrations, and serum creatine kinase levels as a blood marker of muscle damage. Total race time was 320 ± 37 min and jump height (-16.3 ± 15.2%, P < 0.001) and isometric force (-14.9 ± 9.8%; P = 0.007) were significantly reduced after the race in all participants. After the race, the serum concentration of creatine kinase increased by 368 ± 187% (P < 0.001). In contrast, the serum concentrations of essential (-27.1 ± 13.0%; P < 0.001) and non-essential amino acids (-24.4 ± 13.1%; P < 0.001) were significantly reduced after the race. The tryptophan/BCAA ratio increased by 42.7 ± 12.7% after the race. Pre-to-post changes in serum free amino acids did not correlate with muscle performance variables or post-race creatine kinase concentration. In summary, during a half-ironman triathlon, serum amino acids concentrations were reduced by > 20%. However, neither the changes in serum free amino acids nor the tryptophan/BCAA ratio were related muscle fatigue or muscle damage during the race.
authors.affiliation: Exercise Physiology Laboratory, Sports Science Institute, Camilo José Cela University, Madrid, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Areces
authors.affiliation: Exercise Physiology Laboratory, Sports Science Institute, Camilo José Cela University, Madrid, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: González-Millán
authors.affiliation: Exercise Physiology Laboratory, Sports Science Institute, Camilo José Cela University, Madrid, Spain.
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Salinero
authors.affiliation: Exercise Physiology Laboratory, Sports Science Institute, Camilo José Cela University, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Abian-Vicen
authors.affiliation: Exercise Physiology Laboratory, Sports Science Institute, Camilo José Cela University, Madrid, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Lara
authors.affiliation: Exercise Physiology Laboratory, Sports Science Institute, Camilo José Cela University, Madrid, Spain.
authors.forename: Cesar
authors.initials: C
authors.lastname: Gallo-Salazar
authors.affiliation: Exercise Physiology Laboratory, Sports Science Institute, Camilo José Cela University, Madrid, Spain.
authors.forename: Diana
authors.initials: D
authors.lastname: Ruiz-Vicente
authors.affiliation: Exercise Physiology Laboratory, Sports Science Institute, Camilo José Cela University, Madrid, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Del Coso
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000097:blood*; D006801:Humans; D008297:Male; D018763:Muscle Fatigue; D010807:Physical Endurance / Q000502:physiology*; D013177:Sports / Q000502:physiology*
chemical_list: D000596:Amino Acids