I dont think the real danger when running is other people, becuase like what was written in the previous post, a runner obviously is carrying very little of value, is usually in good shape, and hard to catch. Male runners just do not make a good target for bad guys, but they do make a good target for animals. I have been chased in town by dogs that were not leashed, only one ever got close enough to pose a threat, but when he jumped up on me I hit him with a right hand that knocked him back about 2 yards, and seemed to knock him out, then I ran really fast to get away, its amazing what adrenaline can do. If someone were to run in the country, who knows what kind of animals you could run into. So that is one reason for defensive carry for a knife, but I think most people on this forum also like to think about knives as useful tools what if you came across a car accident, and needed to cut someone out of a seatbelt? There are many different situations that a person could come across while on a run, that could require the use of a knife, I have personally run into a rolled over car in the ditch with the people stuck inside, and as previously mentioned have been chased by dogs on several occasions.
Kyle