PHOENIX, Arizona, May 9. THE U.S. Masters nationals began this morning with the 1000 freestyle and wraps up the first day of swimming with the 1650 freestyle in Indianapolis. As we began taping, no national records had been set at the IU Natatorium, but we're bound to see plenty of records fall at this meet. Thirty-nine marks were broken at last year's meet in North Carolina. We'll see if they can beat or match that this weekend.

The first of four days of the Arena Grand Prix in Charlotte, North Carolina begins this afternoon with the women's 1500 freestyle and the men's 800 freestyle, both non-Olympic events but still bound to be much-discussed at meet's end. Katie Ledecky is only swimming in the 1500 this week, and we'll see what kind of time she'll put up. Ledecky will likely get the chance to swim the 1500 at the world championships, where she could chase Kate Ziegler's world record that has stood for nearly six years. The men's 800 will feature NCAA champion Connor Jaeger in his first meet since the NCAAs, as well as training partner Michael Klueh and breakout star Matias Koski, who could be looking to qualify for the world championships for his native Finland. We'll have updates for you as the races happen on Twitter, and complete recaps on swimmingworld.com.