History
The American Motorcycle Association began conducting competition at a variety of distances and for many types of motorcyles soon after the organization was founded in 1924. Its modern racing program, though, began after World War II, when the Grand National series was established. The series combined road racing and dirt track racing at various distances to determine an all-around champion.
In 1976, road racing became a separate championship division with the inauguration of the AMA's Superbike series.
In the meantime, motocross and its American adaptation, supercross, had also become popular in the United States. The AMA created championship series for motocross in 1972 and for supercross racing in 1974.
The most recent addition to the AMA's competitive program is supermoto, which is raced over a track that has both paved and dirt sections. Since the bikes used are based on motocross motorcycles, results are shown here on the motocross championship page.