Table:
text: List of Americas records in swimming
Long course (50 m)
Men
Event Time_ Nationality Date_ Meet Location_
100m backstroke 51.94 United States 8 July 2009 US Championships Indianapolis , United States
200m backstroke 1:51.92 United States 31 July 2009 World Championships Rome , Italy
50m breaststroke 26.76 Brazil 29 July 2009 World Championships Rome , Italy
100m breaststroke 58.96 United States 26 July 2009 World Championships Rome , Italy
200m breaststroke 2:07.42 United States 30 July 2009 World Championships Rome , Italy
50m butterfly 22.76 Brazil 26 April 2012 Maria Lenk Trophy Rio de Janeiro , Brazil
100m butterfly 49.82 United States 1 August 2009 World Championships Rome , Italy
200m butterfly 1:51.51 United States 29 July 2009 World Championships Rome , Italy

Question: Among American swimming records, what is the nationality of the American men in the long distance (50m) with a time of 1:51.51?