Super star tennis player Serena Williams can go the distance on the tennis court but she couldn't make it to the finish line for her own charity 5K run.
Serena got off to a good start in the Serena Williams Live Ultimate Run in Miami but she took a taxi to the finish line.
She sheepishly explained in a Facebook post: "I didn't run the whole way this year, but next year I will."
She cheered on other runners and her sister, Venus, did finish the run.
Sports Illustrated just named her Sports Person Of The Year for 2015.
She also posted the news on Facebook: