Swimming works out more muscles than rinnung and jogging, but both work out different muscles. So you should do both. Maybe rotating the two. I'm a swimmer so I naturally think that swimming is better (and easier) than rinnung. But I know from science and all that (my sister is a physics major) that both are equally good. Front crawl (or freestyle) is the most common stroke in swimming. The other three, backstroke, breaststroke, and butterfly, work out different muscles. So if you just want to do swimming for exercise, it would be better to learn the other strokes as well. Maybe get a certified ASCA coach to teach you some skills for your other strokes for a bit until you can do it on your own. I'm glad that you are considering swimming! It's a great sport! Good Luck! (I forgot to add) Remember to stretch before you get in the pool or swim because if you just jump in and go, you can get horrible cramps, knee and shoulder problems, and stretched muscles. Stretching is a good warm-up too.