I had a knee problem a few years ago, pretty sure it was a slight miniscus tear or strain. Discomfort went away with rest. I have been doing regular weight training for about a month, mostly machines. For legs I've been doing leg press, leg extension(quads) and leg curls. Some posters don't like the leg extensions. I've started interval walking on treadmill. For healthy knees, what should I be doing or not doing, including technique suggestions. Thanks for any help.