The main workout features three full-body circuits, each with five intervals, which you’ll complete twice. You’ll work for 40 ...

You know you should develop a regular exercise routine, but you lack motivation. Promises to yourself are quickly broken, and you never establish enough of the workout habit to experience any rewards.

The science on whether to do cardio before or after weights is inconclusive -- it all depends on your goal: overall health, weight loss or muscle gain. Keep reading to find the best approach for you.