Raszka achieved his first international success at the Junior World Championships in 1988 in Saalfelden , where he and the team won the bronze medal behind the teams from Austria and Norway. Two years later he won the bronze medal in individual at the Junior World Championships in Štrbské Pleso . On December 31, 1990, he made his debut in the ski jumping World Cup in Oberstdorf . He achieved his best result on December 15, 1991 in Sapporo with the 27th place. In the season he started in addition to the World Cup with jumping in the Ski Jumping Continental Cup , where he reached 14th place in the overall standings with 44 points in the 1991/92 season. In 1992 he ended his active ski jumping career.
After his active career, Raszka was actively involved in Masters ski jumping, the series for former ski jumpers. He was able to achieve 4th place at the World Championships with the Czech team in Harrachov in 2002 .