I injured my knee doing HIIT. All that running led to Runner's Knee. Be careful of overdoing it, and rest when your body is telling you too.

I have a bad habit of forcing myself when my adrenaline is pumping, which leads to injuries. I once injured my back doing ab exercises.

Why don't you try the Tabata workout? It is much more intense than the normal HIIT runs, and takes only 4 minutes.