The American sprinter Allyson Felix, 35, won her heat in the 400 meters in 50.84 seconds on Tuesday morning in Tokyo to easily advance to the semifinals of the event, which will be held on Wednesday.

The decorated track star, who has six golds and is running in her fifth Games, told The New York Times Magazine in June that she was looking forward to competing, even though she would have understood if the Olympics had been canceled because of the coronavirus pandemic.

“I would do anything to compete. That’s what the Olympics mean to me. That’s who I am,” she said. “At the same time I understand that a pandemic is going on. We have had so much loss of life, and I don’t want to contribute to any more.”

Felix is also running in the women’s 4x400-meter relay in Tokyo, an event in which she has won three golds. Qualifying heats for that race begin Thursday, with the final on Sunday.

Felix has more medals in track and field — nine — than any other American woman. But as she has grown older, she has also earned increased attention for her work off the track. The difficult birth of her daughter, Camryn, in 2018 caused her to speak out for racial equality in maternal health care. And a 2019 column she wrote for The Times criticizing the maternity policies of Nike, her sponsor at the time — which the company subsequently improved — established her as an advocate for women’s equality in sports.

She talked to The Times Magazine in June about her conflict with Nike, how her perspective on the Olympics had changed since she was a teenager, and how her faith had helped her put her career in perspective.