HIIT in a gym?

[Bobby Digital]

Joined a gym because it's getting too cold to workout in my garage. I've been doing the starting strength program and HIIT sprints, 30 seconds each on 30 seconds off. I usually do this in a field or parking lot but with winter coming this is getting tougher.

I'm trying to replace this with some form of cardio in the gym but everything I've tried sucks. I did 15 "sprints" on an exercise bike, elliptical, and rowing machine, and was barely out of breath after each. My legs were burning and like jello after these but I didn't feel much of a workout. Usually after the sprints I'm drooling, gasping for air, and can't even drive home until I sit down for about 5-10 minutes. The only thing that came close was running on the treadmill but I can't really sprint quickly on a treadmill. Any suggestions? what do people do that visit the gym regularly?

Thinking about switching to steady running for 30-40 minutes, maybe 2 min. sprints on the treadmill? What would be best for burning fat?