The recent improvement of US 5k runners is basically attributed to the realization that to be competitive with the Africans a 13:00 5k is now the minimum requirement. Sure, a 13:15 runner can make either the WC or Olympic finals like Torres and Broe did early this decade. However, to be among the top five 13:00 or under 5k speed might be necessary. Ritz, Teg, and Mottram are simply adapting to this new standard. I am sure now more nations will be producing runners with 13:00 or under 5k speed.