She had her best achievements in short course competitions, where she won bronze at the 2002 FINA World Swimming Championships (25 m) in the 200 m backstroke[2] and six medals, including one gold, at the European Short Course Swimming Championships.

[4] During her career she set 29 national records in the 50–200 m backstroke and various relay events.

[5] Amshennikova was born in Komsomolsk, Ukraine, to Olga Oleksandrovna (Ukrainian: Ольга Олександрівна), a competitive swimmer, and Vitali Alekseevich (Ukrainian: Віталій Олексійович), an amateur track and orienteering athlete.

Her brother Eugene (Ukrainian: Женя) started with swimming but then became a competitive shooter.

In 1997, her local pool was closed for reparations and Iryna moved to Kyiv, where she studied and trained in a boarding school.