legwork vs wild-goose chase

legwork

noun
  • Work, especially research or preparation, that involves significant walking, travel, or similar effort. 

  • Skillful or vigorous use of the legs, as in dance or sports. 

wild-goose chase

noun
  • A futile search, a fruitless errand; a useless and often lengthy task whose execution is inordinately complex relative to the value of the outcome. 

How often have the words legwork and wild-goose chase occurred in a corpus of books? (source: Google Ngram Viewer )