This is a 7 Minute abdominal workout using your own bodyweight or as an option you can use a light dumbbell.
There are 16 rounds of 20 secs work and 10 secs rest. If you can do it twice through that would be fantastic.
Make sure you connect mind to muscle and draw your navel to spine on the effort phase of the exercise. And remember to breath in to prepare and breath out on the effort, never hold your breath!