Unfortunately, motor sports nowadays are dependent on corporate sponsoships and the billion dollar companies that pump millions into advertising spend their money on automobile racing. Another problem is that the giant automakers do a tremendous job of promoting their products through racing. The motorcycle manufacturers can't compete with the Fords and the General Motors of the world. Supercross has developed a solid niche but only an increased popularity by the motorcycle itself will boost its racing popularity. Race car drivers work out constantly year-round.
Most drivers employ personal trainers that monitor their workouts and their diets.
This regimen dictates diet, strength testing, endurance testing, etc. Endurance and stamina are immensley important to race car drivers as intense heat can wreak havoc on a driver. Also the G Forces involved while driving, especially in an open wheel cart, mandate that race car drivers have very strong neck and hand muscles. Because of this, all teams have gymnasiums in their race shops next to their garages. The Castrol Nationals will never outshine the Indy 500 or the Coca-Cola 600 for Memorial Day glory but there are events like the Southern Nationals in Atlanta, The Winston Showdown or the NHRA Finals that could develop into the 'marquee' event that every race series needs to be successful.