Ropek started as a 19-year-old at the first Junior World Championships in 1990 in Älvsbyn, Sweden . He came in 13th place in the individual run and in fifth place together with the Czechoslovak relay. In 1992 his first World Cup season followed, and in 1995 his first World Championships in Detmold . In 1994 and 1996 he finished the World Cup as overall seventh. In 1997 he penetrated the World Championships in Norway with a ninth place on the classic distance also under the top ten. 2001 in Tampere he finished ninth in the newly introduced sprint. The Czech relay with Michal Horáček , Michal Jedlička , Radek Novotný and Ropek as the final runners won bronze in the same championships behind Finland and Norway. At the following World Championships in 2003 in Switzerland, Ropek won silver in the sprint behind the Briton Jamie Stevenson . In 2004 he started in the sprint of the world championships, but did not qualify for the final.
Ropek celebrated further successes as part of the Park World Tour , which he finished second in 1996 and 1999 and won in 1997 and 1998.
Ropek ran for the Czech clubs VŠZ Brno and Dukla Liberec .
