What do you believe?
I believe that if you "want" to do something you will. If you don't want to? Then, you won't. People who say, "I'm not a runner" don't want to run unless you physically can't. That is fine, but don't assume that you are something you are not because you don't want to or have not tried. (By the way I'm not a singer because I won't do karaoke but I don't want to...will I one day? Maybe.)
Many people in my life have found out that they are runners, bikers, swimmers, athletes and all they had to do was try it. Start slow, work towards a goal and often they are rewarded with an improved sense of self, weight loss and a new passion for life.