Effect of off-road competitive motocross race on plasma oxidative stress and damage markers

Br J Sports Med. 2007 Feb;41(2):101-5. doi: 10.1136/bjsm.2006.031591. Epub 2006 Nov 30.


Aim: 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).

Conclusion: The data reinforce the marked metabolic and hormonal demands imposed by motocross, resulting in a condition of enhanced plasma oxidative stress and damage.

MeSH terms

  • Adult
  • Biomarkers / blood*
  • Catecholamines / urine
  • Humans
  • Leukocyte Count
  • Male
  • Off-Road Motor Vehicles*
  • Oxidative Stress / physiology*
  • Sports / physiology*


  • Biomarkers
  • Catecholamines