Don't be scared away by the phrase High Intensity Interval Training, it simply means you are moving from a high intensity segment of time to a low to moderate intensity.
You don't have to run, you don't have to sprint even, it's all high intensity, depending on where your base level is. The better you get at it the higher the high part is, but you increase it with your own strength and speed increase. Start where you are and work your way up! It takes a fraction of the time normal cardio workouts do, its more effective AND it won't deplete the muscle mass you have worked so hard to gain! Win, win training technique.