Option #2: Sprint Tabatas
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 Tabata. As with the option #1 bodyweight routine, you'll complete a total of four four-minute Tabatas to finish the workout.
Post-cardio 10-minute stretch
Don't skip your stretch! Flexibility is one of the five components of fitness, and it's vital to long-term mobility and a pain-free lifestyle.