Cyclocross star Hannah Arensman slams trans participation in women's sports, talks retiring at career peak

Retired cyclo-cross rider Hannah Arensman joined 'America's Newsroom' to discuss her decision to retire and why she decided to push back in the fight for fairness in women's sports. 

Hannah Arensman, a 35-time national cyclocross champion who walked away from her sport at the age of 25 after losing to a transgender competitor in the women’s championships last season, appeared in her first TV interview on "America’s Newsroom" on Wednesday.

Arensman initially revealed her retirement in an amicus brief filed to the Supreme Court in support of a West Virginia law that would have kept transgender female athletes from competing against biological women in sports. During nationals back in December, Arensman finished in fourth place in between transgender women Austin Killips and Jenna Lingwood. She believes it caused her to be overlooked for a spot on the U.S. team for Cyclocross Worlds which occurred in February.

She told Dana Perino she believes transgender women have an advantage over biological females.

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Hannah Arensman competes in 2016. (Tim de Waele/Corbis via Getty Images)

"Absolutely. Biologically, men and women are different," Arensman said. "Men are born with the ability to produce more testosterone and because of that they can build bigger muscles, they have bigger skeletal structure, they will develop a bigger heart, bigger lungs and so when you can pump more blood through your body quicker – when you can get more air into your lungs and into your cells – that produces a lot of differences in power."

Arensman said Killips proved to be able to run faster, and it did not matter about what was happening with some of the technical sections of the course.

"But it