I was just a runner until I learned to swim. Now I do both. Not because one is better that the other but because having an alternative keeps you interested and involved. Bored of running? Swim a while, and vice versa. Now, if we talk from the perspective of the muscles involved, swimming is the way to go since your body gets a better workout. Also swimming can and will cost some money since you have to pay a membership while running is free, just go the park.
