Breakdown: Jaworski has run this distance just three times in her career, but she enters the U20 ranks with a real shot to medal. She's ranked No. 7 in the field with her US no. 1 of 57.63 from USA Juniors--just behind LSU's Jurnee Woodward--and could put together a solid race. In a lot of ways, it was incredible that Jaworski qualifed in the first place--beating out Masai Russell, who was third in the 400mH last year at the Pan American Junior Championships--so the fact that she's in this race should say something. She's also still in high school, with one more year left at Wasau West. No one is expecting Jaworski to go after Sydney McLaughlin's national record of 53.82, but if the Wisconsin native can push under 57 seconds, she would be one of just six other to have accomplished that feat all-time.