3 tabatas in a row, 20 seconds on 10 seconds rest. Repeat 8 times for a total of 4 minutes. Keep track of your lowest score to motivate you to go harder the next time.
Tabata #1: air Squats
Tabata #2: crunches or sit-ups
Tabata #3: push-ups
Rest for about for a few minutes between each, no more than 5 and feel the burn in your muscles!!