Leerdam had her first international successes at the 2017 Junior World Championships in Helsinki . There she won the bronze medal over 3000 m and 500 m and the gold medal over 1500 m and in the mini four-way fight. The following year she won the silver medal in the Junior World Championships in Salt Lake City in the mini four-way, over 500 m, 1000 m, 1500 m and over 3000 m and the gold medal in the team sprint and in the team pursuit. At the beginning of the 2018/19 season, she started the World Cup for the first time in Obihiro , finishing 13th and 11th over 500 m and tenth place over 1000 m. In the team sprint, she achieved her first podium finish in the World Cup with third place. At the following World Cup in Tomakomai , she won her first World Cup victory in the team sprint.
Personal bests
500 m 37.30 sec. (installed on February 14, 2020 in Salt Lake City)
1000 m 1: 11.84 min. (installed on February 15, 2020 in Salt Lake City)
1500 m 1: 54.31 min. (installed on March 9, 2018 in Salt Lake City)
3000 m 4: 05.19 min. (installed on March 10, 2018 in Salt Lake City)