U.S. athletes take on the world in the Penn Relays at Franklin Field. Allyson Felix, Tyson Gay, Jeremy Wariner and Lauryn Williams will all be competing in the meet.

The U.S. will compete against 150 athletes from 11 countries hoping to gain their spots on the Olympic team.

“The 4×400 will always be my main focus,” 2006 IAAF World Athlete of the Year Sanya Richards said Friday. “But I definitely want to get some more fast 100s and 200s in this year.

“I really want to be part of the 4×100 relay team. That’s why I’m running it here, and throughout the season, hopefully I’ll be one of the four fastest Americans in the 100s.”

Read more: American athletes warm up for Olympics at Penn Relays