QUOTE(D35TR00 @ Nov 12 2009, 12:13 AM)
If your legs feel fine then more power to you but why only 20 mins??? You are doing other training, RIGHT?
Treadmills could be hard on the knees. Ellipticals are probably your best bet. There is a very good cheap one called the Gazelle. See the pics below;
http://www.rabboar.com/studio/images/gazelle.jpgYou should really try to get out for a run every once in a while though.
I use to go to a boxing gym by my house all the time but don't go as much right now because of school. I just go to workout at the gym to stay in somewhat decent shape because I eat a lot of junk.
I usually run hard on the treadmill for 10 minutes then jog for another 10. I also do the elliptical for 10 minutes. I sometimes use the bench and other machines at the gym but mostly workout at home and stick to pushups, sit ups and bicep curls. Also do squats.