Complex sentence: She set a new world record of 11.3 for the 100m in Poland in 1955, and in the 1956 Olympics she won gold again in the 80m hurdles and with the Australian 4x100m relay team.
Split into simpler sentences: She set a new world record of 11.3 sec for the 100m in Poland in 1955. In the 1956 Olympics she won gold again in the 80m Hurdles and in the 4x100m relay team.