Caitlyn Jenner says her past identity struggles helped her become one of the greatest athletes in the world.

In a new trailer for Netflix’s Untold, a five-part documentary about the greatest moments in sports history, the Olympian looks back on her athletic career, which included winning a gold medal in the decathlon at the 1976 Summer Olympics, and discusses how the sport was shaped her Gender identity for a long time.

“I’ve always had these problems,” she reflects in the exclusive footage from E! News. “But without her, I would never have achieved what I did.”

The Keeping Up With the Kardashians star announced in April 2015 that she is transgender. A few months later, she re-introduced herself to the world as Caitlyn. And, as Caitlyn notes in the trailer, she “always had to deal with confusion in my soul,” but participating in exercise helped her feel part of her. As she put it, “That changed everything. So I built this Bruce character.”