i do cardio exercises but i want to do crunch..which should be done first?

Answer 1

Crunches or weight lifting are anaerobic exercise.During anaerobic exercise you burn glycogen(stored carbohydrate) for fuel.This can also happen during cardio but there are many factors that have to be in place for you to burn fat during.Do ALL anaerobic work before your cardio.This is one way to ensure you'll burn more fat during cardio.You'll deplete your glycogen stores and burn more fat by ketosis.
Clinical testing has shown this to be so.You can do something light before the crunches but that isn't necessary.Always do anaerobic exercise first the cardio vascular.This also gived you the enegy you need to complete your ab work out.It will also increase the likelihood that you will train your abs rather than doing the cardio and saying "that's enough,I'm going home".

Answer 2

cardio first then crunch