come London in July but the thing that strikes you about this domestic affair as you walk into the US Olympic swim trials in Omaha for the first time is the size of things. Many and complex are the reasons why the USA is the world's leading swim nation but one of the answers to the question 'why do they more often step up at the big one when others shy away from best' is here in this temporary pool sunk into the convention center: they've seen it all (and walked it all) before at home when many others will have seen nothing like it until they head out into the lights on a global stage. The London Aquatics Centre, for example, is certainly no bigger than this venue in terms of many of the internal factors that can turn swimmers into rabbits in headlights. At the Olympic test event in March, audiences of about 2,000 were typical but most of those were there for British trials and left the building before international competition got underway. In Omaha this evening: more that 12,000 spectators for the show. There'll be no fireworks of the kind that curl your hair 20 rows back as they explode deckside with each passing addition to the US squad but even as the world catches up with such things the US still has a clear edge. Dana Vollmer, coached by Terri McKeever at Cal, was a case in point as she stepped up for the final