If you read my post (which on a forum like this I shouldn't expect) you'd see that I acknowledge every race has it's good and bad examples. There is no set genetic formulat that guarantees anything, however, certain races have tendencies that are more likely to prevail than in others. As I pointed out, an argument could definitely be made that culture has as much to do with it as genetics, but aboriginal (and polynesian) athletes have a tendency to be fantastic front-runners, but poor when they are coming from behind.
Now you could make a magnitute of assumptions about this, I simply believe that with aboriginal athletes in particular, you have a higher chance of encountering an athlete who do not give their full ability in certain situations. On the contrary I believe that you have a higher chance of finding an aboriginal athlete who tends to become an even-better performer when they are in a position of power - this is most likely a confidence thing (which would lead to me arguing it's more cultural than genetic).