The heats of the USA Swimming Grand Prix in Indiana this morning served as a reminder to those in the thick of Olympic trials season that the warm-up for London 2012 has barely begun - and the need for easy speed going through will be the sum of Olympic drop for some come the summer.

Clark Burckle, 24 and racing for Tucson Ford Deal, cracked out a 2:09.72 in the 200m breaststroke to become the 4th man this year to break 2:10, his time the second best anywhere in the world just shy of the 2:09.33 in which Bath's Andrew Willis won the British Olympic trials ahead of training partner Michael Jamieson, on 2:09.84, with Loughborough-based Luxembourg international Laurent Carnol on 2:09.78 back in January.

As the morning unfolded in Indiana, it wasn't hard to see that the standard at Omaha come late June when the US gathers over eight days to select its 2012 Olympic squad will surely confirm the latest stroke of progress in the ranks of the world No1 swim power.

After Micah Lawrence, 21 and of SwimMAC Carolina, clocked 2:25.77 (third best in the world so far this year and inside anything at Britain, Australia and France trials), in the heats of the 200m breaststroke to set up a final with Caitlin Leverenz, of Cal, and 2004 Olympic champion Amanda Beard, Tuscon, Nathan Adrian, Cal, limbered up with a lead time of 49.04 in the 100m free.

Next up was another sunb-soaked California-based ace, Dana Vollmer, on 54.26 in the 100m free not too long before she got back in and registered a 57.58 in the 100m butterfly, off a 26.74 split, with training partner at coach Terri McKeever's squad, Leverenz, on 59.52 as she gears up for an assault on the domestic medley ranks she must get past to take on the international foe she is less familiar with.

If the free heats left Vollmer just outside the world top 10 for 2012 and ahead of a field that includes Missy Franklin, Amanda Weir, Allsion Schmitt, Jessica Hardy and Kara Lynn Joyce, the 'fly effort of the Shanghai 2011 world champion was 4th best in the world so far and a season best a touch quicker than the tapered effort of Commonwealth champion Alicia Coutts (AUS). A touch to go to get to the top efforts of Britain's best, Ellen Gandy and Fran Halsall, with Sarah Sjostrom (SWE) the sole sub-57sec swimmer of the year so far.

Schmitt, of Baltimore, will also take in the 400m free this evening, alongside Olympic silver medallist Katie Hoff, while the men's 100m 'fly will feature a man who has trained in the same squad as both women under the guidance of Bob Bowman then and now, Olympic and world champion and record holder Michael Phelps, third through this morn on 53.20.

The session also saw Ryan Lochte race 100m free and 100m 'fly outside the top 8. Phelps and Lochte are due to race the 200m medley at the meet but will be at different stages of the longer game, the race unlikely to scatter insightful runes on the road to London - though you never know until the clock stops.