i'd say most top 50-100 guys can run a 5k in 18 or under, would be surprised if they couldnt.
i can run a 20:00 on a hungover morning without even training so YES these guys can easy IMO
once new a guy that never practiced only should up for races, usually late, always smoking cigs and could run 15 flat...with jean shorts
looking at someone means nothing
4 kblades 16x19, alu rough/syn high 40s