follow through vs follow up

follow through

verb
  • To execute or complete a commitment. 

  • to continue moving the arms (and any held implements, such as a bat or club) or legs after striking e.g. a ball. 

  • To defecate unintentionally as a result of a cough or sneeze, etc. 

follow up

verb
  • To take further actions remaining after an event; to continue, revisit, or persist; especially, to maintain communication or verify. 

How often have the words follow through and follow up occurred in a corpus of books? (source: Google Ngram Viewer )