Motocross linked to damaging physical stress

NEW YORK (Reuters Health) - Participation in the sport of motocross seems to cause a number of physical changes that may damage muscle and other tissues in the body, Portuguese researchers report. Whether these effects impact performance and whether antioxidant vitamins can help remains to be determined.

Motocross is a type of off-road motorcycle race run on bumpy tracks that use natural terrain features or man-made jumps and obstacles. The racers typically perform a variety of dramatic jumps, twists and turns, and other maneuvers while traveling at break-neck speeds.

The sport puts a considerable amount of strain on the arms as the rider compensates for the bumpy terrain. This so-called "arm pump" coupled with the adrenaline surge that typically accompanies motor sports may cause oxidative stress, a term used to describe the generation of hydrogen peroxide and related chemicals that can damage body tissues.

Numerous reports have supported a pro-oxidant effect for exercise, but the present study, reported in the British Journal of Sports Medicine, is the first to specifically look at the impact of motocross on oxidative stress.

Dr. Antonio Ascensao, who is on the faculty of sports science at the University of Porto, and colleagues used various blood tests to assess oxidative stress in 10 male top-level riders before, immediately after, and 1 hour after a motocross race.

The result of the laboratory tests showed that the riders experienced a significant increase in oxidative stress and damage following completion of the race, the report indicates.

The implications of these effects, however, are unclear, the researchers note.

"Although the direct effects of enhanced oxidative stress on exercise performance are inconclusive," the investigators add, the findings may serve as a "starting point" for studies to evaluate the potential benefits of antioxidant supplements on motocross performance.

SOURCE: British Journal of Sports Medicine, February 2007.