I agree, and thats why I said it would be bad to do after a
weight training workout. I only mentioned it because its believed to (and I also think its correct) burn more calories. But after a
weight training workout...or even the day after working out legs, I would stick to the 30% of your max at an incline for about 30-40 minutes or so. Not so much as to stress the legs, but enough to get your heart rate up. Oh, and thats 30-40 minutes on an off day (not
weight training). If you're going to do this on the same day as
weight training, I'd cut it to about 20 minutes because your body is already semi-fatigued.