20 Rounds (30 Minutes):
30 Seconds Sprint*
1 Minute Rest

* Sprint can be on a track, done "suicide sprint" style on a basketball court or field, etc.  On a treadmill, just set two paces.  Your sprint pace (should be faster than your regular mile pace) and a walking pace.  Cycle back and forth for approximately 30 seconds/1 minute.  

Posted on January 4, 2015 .