Runner times influenced by language?

Ever since I went to cheer K on running the Tufts 10K, I've wanted to graph the results. Something about knowing they post the times of some 6000 runners made me curious. I was initially curious to see if the results simply formed a straight bell curve or if there were a couple of different "humps" corresponding to different sorts of runners (I could imagine a "competitive runner" hump and a "I want to prove I can make it" hump, for example).

Those results didn't turn out to be that interesting, but one thing did strike me as interesting. The top of the curve, quite incredibly and by a rather dramatic margin, is precisely at one hour. This begs some questions:

1. If there were 55 minutes in an hour, would all of these women have trained just that much harder?

2. Are there other athletic events where even numbers affect performance? Numbers of homeruns? Minutes in a mile?

3. (this one I could check if I felt like it -- maybe I will soon): is this result reproduced in other 10ks? Is there a similar peak at even numbers for other distances?