Option #2: Sprint Tabatas
If you prefer to do your cardio outside, you can't go wrong with a sprint Tabata. After doing your five- to 10-minute warm-up, sprint as fast and as far as you can for 20 seconds, rest 10 seconds, then repeat, performing a total of eight rounds. After you finish a Tabata, walk slowly for a minute to recover, then dive right into the next one. As with the option #1 bodyweight routine, you'll complete a total of four four-minute Tabatas to finish the workout.