arm wrestling vs showdown

arm wrestling

noun
  • A strength sport with two participants, in which each participant grips the other's hand and tries to pin the other's arm onto a surface. 

showdown

noun
  • The final battle between two nemeses, in which there can be but one victor. 

  • The final round in a poker match, where the all remaining players' cards have to be put down on the table and shown. 

How often have the words arm wrestling and showdown occurred in a corpus of books? (source: Google Ngram Viewer )