Bill Phillip's Back To Fit: Day 54
Kick it up a notch, and make today's cardio workout really count!
You should be picking up the speed now. Make sure to write down the speed levels on your apparatus. Note how long you can keep up a sprint at a certain speed, then try to do better next time.
If you're sprinting along and you can't keep the speed up, turn it down a bit to finish your minute run. That run is the most important part of HIIT training. It's in that minute where challenges are created and overcome. Kick the speed up a notch, adjust, and push yourself harder in that time span. You'll feel rewarded when you get to walk and catch your breath.