Wow!! I am so much too lazy to officially work out. However, in the summer I ride my dirt bike 3-5 days per week. Serious trail and track riding and motocross is the most strenuous sport you can do, with the exception of soccer. Honestly!! You truly do not sit on your butt and ride, unless you want a broken neck, back, torn ACL tendon in your knee, or worst case scenario--dead.
When riding I tone up very fast and get an amazing amount of cardio.