I'm not big on cardio stuff, but my soccer season is starting soon and I need to take it easy on my legs due to some nasty shin splints. I want to avoid running as much as possible so my shins can heal before the season, and my physical therapist said its cool to use the bikes and some of the other "running equipment." I want to do cardio before the season to get my lungs/heart back into shape. I know that when I run around a track I get winded quickly, which is what I want, because that will build endurance. When I try to use the bikes and running machines at the gym, I dont really get that winded feeling. I just get really tight legs afterwards, even when I set the level to the highest and run for 20 minutes on them. Can ANYONE recommend specific machines that will actually give me the sensation that I'm running (being winded so I can build endurance) without putting too much pressure on my shins? If anyone could also provide pictures/animated gif's of the machine (exrx.net) that would be cool. I'm just trying to find out what you guys have found as an effective cardiovascular substitute to running.