title: Sarcomere Disruptions of Slow Fiber Resulting From Mountain Ultramarathon.
abstract: OBJECTIVE
  To investigate changes after a mountain ultramarathon (MUM) in the serum concentration of fast (FM) and slow (SM) myosin isoforms, which are fiber-type-specific sarcomere proteins. The changes were compared against creatine kinase (CK), a widely used fiber-sarcolemma-damage biomarker, and cardiac troponin I (cTnI), a widely used cardiac biomarker.
  
  
  METHODS
  Observational comparison of response in a single group of 8 endurance-trained amateur athletes. Time-related changes in serum levels of CK, cTnI, SM, and FM from competitors were analyzed before, 1 h after the MUM, and 24 and 48 h after the start of the MUM by 1-way ANOVA for repeated measures or Friedman and Wilcoxon tests. Pearson correlation coefficient was employed to examine associations between variables.
  
  
  RESULTS
  While SM was significantly (P = .009) increased in serum 24 h after the beginning of the MUM, FM and cTnI did not change significantly. Serum CK activity peak was observed 1 h after the MUM (P = .002). Moreover, serum peaks of CK and SM were highly correlated (r = .884, P = .004).
  
  
  CONCLUSIONS
  Since there is evidence of muscle damage after prolonged mountain running, the increase in SM serum concentration after a MUM could be indirect evidence of slow- (type I) fiber-specific sarcomere disruptions.
authors.affiliation: National Inst of Physical Education of Catalonia, Barcelona, Spain.
authors.forename: Gerard
authors.initials: G
authors.lastname: Carmona
authors.forename: Emma
authors.initials: E
authors.lastname: Roca
authors.forename: Mario
authors.initials: M
authors.lastname: Guerrero
authors.forename: Roser
authors.initials: R
authors.lastname: Cussó
authors.forename: Alfredo
authors.initials: A
authors.lastname: Irurtia
authors.forename: Lexa
authors.initials: L
authors.lastname: Nescolarde
authors.forename: Daniel
authors.initials: D
authors.lastname: Brotons
authors.forename: Josep L
authors.initials: JL
authors.lastname: Bedini
authors.forename: Joan A
authors.initials: JA
authors.lastname: Cadefau
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000293:injuries*; D024461:Myosin Type I / Q000097:blood*; D010807:Physical Endurance / Q000502:physiology*; D012420:Running / Q000502:physiology*; D012518:Sarcomeres / Q000378:metabolism*; D024744:Skeletal Muscle Myosins / Q000097:blood*; D019210:Troponin I / Q000097:blood
chemical_list: D015415:Biomarkers; D019210:Troponin I; D003402:Creatine Kinase; D024461:Myosin Type I; D024744:Skeletal Muscle Myosins