It is all about in/out.
Isolation exercises, such as most abdominal work, burn very very very few calories. They will make the muscle "harder", but do very little to burn calories.
Steady State Cardio will burn more calories at the time of the workout, but little afterburn.
HIIT will burn serious calories during the workout, but you get the benefit of afterburn, as with weightraining.
A good fat burning routine will combine all three things - assuming, of course, diet is already 100% clean.
Isolation exercises, such as most abdominal work, burn very very very few calories. They will make the muscle "harder", but do very little to burn calories.
Steady State Cardio will burn more calories at the time of the workout, but little afterburn.
HIIT will burn serious calories during the workout, but you get the benefit of afterburn, as with weightraining.
A good fat burning routine will combine all three things - assuming, of course, diet is already 100% clean.