I have to say that I think that both is possible. I haven't been seeing myself as having any running capabilities at all but after doing some running workouts continuously for a couple of months I can say that you can get stunning results really fast if you are motivated and keep pushing yourself. The first weeks your legs feel so stiff but it gets better and once you are able to just focus on the running and not have any really pains while doing so you quickly feel how good your overall condition will help you run fast and maintain high speeds for quite a while.