: The premier class featuring the most powerful 450cc four-stroke motorcycles and the sport's top-tier professional athletes.

Professional racing is divided into two primary engine displacement classes based on the American Motorcyclist Association (AMA) Rulebook :

Supercross is a high-intensity form of off-road motorcycle racing that takes place on man-made dirt tracks constructed inside stadium venues. Originally born in 1972 as the "Superbowl of Motocross," it has evolved into a premier global sport known for its technical jumps, rapid-fire decision-making, and close-quarters racing. Core Competition Classes