Original sentence: At the German Championships in Berlin on 27 June 2009, Steffen clocked 52.56 in the women's 100m freestyle event, breaking the world record and upstaging the previous record of 52.85 set by herself two days before..
Edited sentence: At the World Championships in Rome on 31 July 2009, Steffen clocked 52.07 in the women's 100m freestyle event, breaking the world record and upstaging the previous record of 52.22 set by herself four days before..