forget minutes here, where talkin seconds. You can use the elliptical if your damaged or not really conditioned but i recomend pounding the sprint track or oval or whatever you can find and doing some good old fashioned sprints! I do two different sprint sessions at the moment. 1 consists of 15 100 mtr sprints with a walk back recovery [but start with 10 and add another one each week till you hit 15]. The other goes like this:
1 x 800 mtr sprint w/ 5 minute rest
2 x 400 mtr sprints w/ 3 minute rest
2 x 200 mtr sprints w/ walkback recovery
4 x 50 mtr sprints w/ walkback recovery.
But you can tailor HIIT to suit yourself with sprints, swimming, weights whatever. Just remember to make it short burst of HIGH INTENSITY. hope this helps bro.