After a couple of low-key workouts, it's time for one last killer conditioning routine designed to torch your major muscle groups while raising your heart rate. Leave it all on the line and push yourself -- the entire routine takes less than 25 minutes.
Today’s workout is five minutes of stair climbing, followed by four four-minute Tabatas. You'll get one minute of rest between each series. Find a stairwell, get your timer ready, and be prepared to work.