This doesn't sound like a good study to me because of the two groups they are comparing. Even in the original article (which I only had a brief look at), it see

This doesn't sound like a good study to me because of the two groups they are comparing. Even in the original article (which I only had a brief look at), it seems they didn't do a really fair comparison but compared two completely different groups with each other. With the same study, they could also have said "people with more brain connections feel a stronger urge to run long distances". A better study would have been to take a group of lazy people, divide them into two groups, one will do long distance running in the next year, one won't, and an additional group of current runners divided into the same groups. Then I would start believing this. Right now it sounds just like a flawed first-time study an undergrad did.