title: Serum creatine kinase activity and its relationship with renal function indices in professional cyclists during the Giro d'Italia 3-week stage race.
abstract: OBJECTIVE
  To analyze the behavior of total creatine kinase (CK) and other muscular damage markers and to compare CK activity and renal function indices in professional cyclists during a 3-week stage race.
  
  
  METHODS
  Prospective, noncomparative, interventional.
  
  
  METHODS
  The athletes were recruited during the 2011 Giro d'Italia.
  
  
  METHODS
  Nine professional road cyclists from the Liquigas-Cannondale team and competing in the race.
  
  
  METHODS
  Blood samples were collected on the day before the start of the race, on day 12, and on the final day (day 22) of the race.
  
  
  METHODS
  : Creatinine and cystatin C concentrations, CK, lactate dehydrogenase (LDH), and aspartate aminotransferase (AST) activities were measured. The estimated glomerular filtration rate was calculated according to equations based on creatinine, cystatin C, or both.
  
  
  RESULTS
  Creatine kinase and AST activity increased during the second part of the race, and LDH activity progressively increased during the entire course of the race. There was a negative correlation between CK activity and the delta prerace-day 12 of glomerular filtration rate, as obtained with simple cystatin C or with Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine and cystatin C equations.
  
  
  CONCLUSIONS
  The effect of prolonged strenuous muscular effort on biochemical laboratory parameters in professional road cyclists was confirmed. The correlation observed between renal function and CK activity underscores that measurement of cystatin C is more accurate than creatinine alone in the evaluation of renal function and that it is unaffected by response to physical stress-induced muscular damage.
authors: Laboratory of Experimental Biochemistry and Molecular Biology, I.R.C.C.S. Istituto Ortopedico Galeazzi, Milano, Italy. alessandra.colombini@grupposandonato.it
authors: Alessandra
authors: A
authors: Colombini
authors: Roberto
authors: R
authors: Corsetti
authors: Marco
authors: M
authors: Machado
authors: Machado
authors: M
authors: Marco
authors: Rosa
authors: R
authors: Graziani
authors: Giovanni
authors: G
authors: Lombardi
authors: Patrizia
authors: P
authors: Lanteri
authors: Giuseppe
authors: G
authors: Banfi
mesh_terms: D000328:Adult; D056352:Athletes; D001642:Bicycling / Q000502:physiology*; D003402:Creatine Kinase / Q000097:blood*; D005919:Glomerular Filtration Rate; D006801:Humans; D007668:Kidney / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D003402:Creatine Kinase