I wanted to switch up this 13 minute core workout by trying out some new moves and using the 40/20 format. 40 seconds of work followed by 20 seconds of rest. There are 6 intervals in a row, then a one minute break. Then, the exercises change for the next 6 intervals.
You will need a mat and one dumbbell. I'm using an 8 lb weight. Don't go too heavy.