How does burning calories work?

Recently we have done a couple part B workouts where it was nothing but a quick and dirty ride on the Assault Bike. The first was 50 calories for time and the most recent was a max calorie ride in 3 minutes.  Both were pretty equally gnarly.  This was indirectly the inspiration for this blog post because I heard several people say something along the lines of, “After all that, I only burned 50 calories??”  This would be alarming but luckily the extra calorie-burning action doesn’t stop as soon a...