During his gymnastics career from 1971 to 1981, Gienger won 36 German championship titles; one gold and three silver medals in world championships; three gold, two silver and two bronze medals in European championships, and one Olympic bronze medal.
Gienger was an outstanding high bar artist: He won the European Championships in 1973, 1975 and 1981; he won gold in the 1974 World Championships, and won the bronze medal in the 1976 Olympic Games.