What is the fine-grained topic of the following text: This is amazingly cool because many Olympic level runners use these indoor races as “tune-ups.” For example, last year we spent the entire weekend watching the games live and got to see Sanya Richards Ross, Bernard Legat, Galen Rupp, and Justin Gatlin do their speedy thing as an Olympic warm-up (along with Sara Hall…so Ryan Hall was somewhere in my general vicinity!). Only return the topic.
Olympic level runners using indoor races as warm-ups