title: Effect of off-road competitive motocross race on plasma oxidative stress and damage markers.
abstract: OBJECTIVE
  To analyse the effect of an off-road motocross heat on plasma levels of oxidative stress and damage, blood leucocyte counts and urine catecholamine concentration.
  
  
  METHODS
  Plasma contents of total, reduced and oxidised (GSSG) glutathione, %GSSG, malondialdehyde (MDA), protein carbonyl and sulphydryl groups, total antioxidant status (TAS), uric acid, and blood neutrophil and lymphocyte counts were evaluated in 10 male top-level riders before, immediately after (0 h) and 1 h after a simulated competitive motocross race. 24-h urine adrenaline, noradrenaline and dopamine concentrations were also measured.
  
  
  RESULTS
  The motocross heat resulted in an increase in plasma oxidative stress and damage (p<0.05). This was shown by a significant increase in %GSSG, TAS, MDA and carbonyls, and by a decrease in sulphydryl groups after the race. There was a significant increase in both plasma uric acid and urine catecholamine concentration after the race (p<0.05). Blood neutrophil counts increased at 0 and 1 h after exercise (p<0.05). Lymphocyte count increased from baseline to 0 h, although it decreased from baseline and 0 to 1 h after exercise (p<0.05).
  
  
  CONCLUSIONS
  The data reinforce the marked metabolic and hormonal demands imposed by motocross, resulting in a condition of enhanced plasma oxidative stress and damage.
authors.affiliation: Research Center in Physical Activity, Health and Leisure, Faculty of Sports Sciences, University of Porto, Porto 4200-450, Portugal. aascensao@fcdef.up.pt
authors.forename: António
authors.initials: A
authors.lastname: Ascensão
authors.forename: Rita
authors.initials: R
authors.lastname: Ferreira
authors.forename: Franklim
authors.initials: F
authors.lastname: Marques
authors.forename: Eduardo
authors.initials: E
authors.lastname: Oliveira
authors.forename: Victor
authors.initials: V
authors.lastname: Azevedo
authors.forename: José
authors.initials: J
authors.lastname: Soares
authors.forename: José
authors.initials: J
authors.lastname: Magalhães
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood*; D002395:Catecholamines / Q000652:urine; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D015541:Off-Road Motor Vehicles; D018384:Oxidative Stress / Q000502:physiology*; D013177:Sports / Q000502:physiology*
chemical_list: D015415:Biomarkers; D002395:Catecholamines