For combo moves (i.e. plank + rocking plank), take a 10- to 30-second break between exercises. The amount of time will be dictated by your level (beginner, intermediate, or advanced).
For circuits, do all exercises back to back without rest; where there are multiple rounds, take a maximum of 60 seconds of rest between rounds.
When it comes to plank holds, you can do either the straight-arm plank or the forearm plank. You can also mix things up by doing half of the holds in one plank and half in another. For example: If you're doing 30-second plank holds, do 15 seconds in forearm plank and then 15 seconds in straight-arm plank. Or, try a forearm plank in one round of a circuit and a straight-arm plank in the second round.
Be sure to record your plank time on Day 1 and the bonus Day 31 (don’t worry, the plan officially ends after 30 days!), so you can track your progress.
Rozalynn S. Frazier, Health senior fitness editor, is a NASM certified personal trainer.