Doug Henry was a three-time AMA Motocross national champion in the 1990s. He was on the leading edge of a revolution in professional motocross racing by becoming the first prominent rider to race four-stroke machines in national competition against a sea of traditional two-stroke motorcycles. Just a few years after Henry became the first four-stroke rider in AMA Motocross history to win a national championship in 1998, AMA Motocross Championship racing would become almost exclusively the domain of four-stroke bikes. After retiring from motocross full-time, Henry went on to become one of the leading Supermoto riders in the world.