Paralympic gold medalist Allysa Seely and American teammate Hailey Danz finished second and third, respectively, at the ITU Paratriathlon World Championships in Lausanne, Switzerland, in September.

Ms. Seely is a 2007 graduate of Mountain Ridge High School.

Ms. Seely, a three-time world champion who made history by winning a gold medal in paratriathlon’s debut in the Paralympic Games Rio 2016 and dominated PTS2 since then, won a silver medal at the world championships for the second time in three years.

She was among seven U.S. paratriathletes winning medals.

Ms. Seely is the defending champion in the women’s PTS2 division. She went undefeated during the 2018 season, topping off her efforts with a gold medal at the 2018 ITU Paratriathlon World Championships in Gold Coast, Australia. She has extended her winning streak in ITU World Paratriathlon Series races this year, winning all three of the 2019 regular-season WPS stops in Milan, Yokohama and Montreal.

Ms. Seely, 30, is a Glendale native and currently calls Colorado Springs, Colorado, her home.

According to teamusa.org, she became involved in triathlon as a New Year’s tradition to try something she had never done before. She learned about triathlon and signed up for her first race a few weeks later.

Ms. Seely was a member of the Arizona State University collegiate club triathlon team and a nationally ranked triathlete before her diagnosis. In 2010, Seely was diagnosed with Chiari II Malformation, basilar invagination, and Ehlers-Danlos Syndrome, which affect her brain, spine, and connective tissues. After her first surgery, she was back to competing seven weeks later at the USA Triathlon Collegiate National Championships with ASU. She made her debut as an elite paratriathlete in 2012, earning bronze at the ITU Paratriathlon World Championships that year. Then in 2013, Ms. Seely had her left leg amputated below the knee due to complications and increased spasticity in her foot. That would move her into a new paratriathlon category — but she continued to thrive, winning five gold medals on the elite ITU circuit in 2014. She earned her first two world championship titles in 2015 and 2016.

At the Rio 2016 Paralympic Games, she made history by winning a gold medal in paratriathlon’s debut as a Paralympic medal event. That same year, she was a featured athlete in ESPN the Magazine’s Body Issue.

She has been dominant in the women’s PTS2 division since Rio, earning silver at the 2017 world championships and winning her third career world title in 2018. She was undefeated in the 2018 ITU World Paratriathlon Series, and is undefeated to date in the 2019 series.

In July of this year, Ms. Seely won an ESPY for Best Female Athlete with a Disability.