Before I was enlightened, the only thing I would do for exercise is run. Run, run, and run some more. I hated every second of it, but I had always considered it the only exercise I could do with no money and equipment. My knees hurt terribly, and the shape of my feet didn't help. I have completely flat feet and a hammer toe on my right foot.
I eventually began doing more bodyweight exercises. Pushups and situps, you know what I mean. They were good, but the results weren't particularly astounding.
However, I soon discovered
this book, and
its forums. Both are great. The book has a great wealth of exercises and information, and the forums are full of the most helpful people to assist you in your initiation into the world of bodyweight exercises. The exercises aren't just scores of pushups and situps. They implement exercises called DVRs and DSRs. Isometrics are also a large part of this kind of lifestyle.
I stopped all cardio training. Period. We had to do a 2 mile run for gym class, and I was doing better than ever before. I'm really pleased with the results.
Running never seemed to help. It seems like most runners are either twig-skinny, or one of the endless number of "skinny fat people". You see hordes of them at every marathon. Flab everywhere, muscle nowhere.
I'm probably opening myself up for flaming on a forum where every other person is a runner; oh well. Sue me.