US Olympic trials get underway today - but Michael Phelps has reduced his workload to just eight events, dropping the 400m freestyle before action begins.

The name of the world 200m free is missing from the 400 free heat sheets released late on Saturday. The move is hardly unexpected: there is a limit to how many times a swimmer can get up at a Games and face new opponents who are fresh, even for a man who sets himself no limits.

Given that Phelps has said that he wishes to reduce his schedule after Beijing to sprint events and races up to 200m, the 400m freestyle may remain one event in which we may never see Phelps' full potential unfold.

Coach Bob Bowman had already hinted that he would drop the event. Phelps opens his account today in the 400m medley and will meet one of those who are likely to cause him the greatest trouble this summer, Ryan Lochte, who is entered in 11 events. Like Phelps, Lochte will probably end up not racing all of the races he entered, at least not past prelims.