Transgender swimmer Lia Thomas ended her controversial college swimming career with a last place finish in the final of the 100m freestyle at the US collegiate champsionships on Saturday.

Thomas, who competes for the University of Pennsylvania, trailed home in eighth place in 48.18sec, more than two seconds behind winner Gretchen Walsh, who touched the wall in 46.05sec.

Thomas, who swam on Penn’s men’s team before switching to the women’s squad this season, became the first transgender athlete to win a top-tier National Collegiate Athletic Association (NCAA) crown when she won the 500m freestyle title on Thursday.

She finished fifth in the 200 free final on Friday.

Thomas was seeded 10th in the 100m freestyle but finished second in her morning heat in 47.37 seconds, her best time of the season, to qualify fourth overall for the final.

Controversy has shrouded Thomas throughout the year, with critics and some fellow swimmers saying she should not have been allowed to compete and has an unfair physiological advantage. Others say she should be allowed to compete freely as a woman.

Speaking after her Thursday victory, Thomas said she had tried to calm the controversy.

“I try to ignore it as much as I can, I try to focus on my swimming, what I need to do to get ready for my races and try to block out everything else,” Thomas said.

Last month, governing body USA Swimming unveiled new guidelines that included a more stringent threshold for testosterone.

But the NCAA, the governing body for US college sport, decided those rules would not be applied to the championships, saying to do so would have “unfair and potentially detrimental impacts” on athletes preparing for the meet.