fire up vs overstrain

fire up

verb
  • To excite; to infuse with energy. 

  • Of an engine or similar, to start. 

  • To ignite. 

  • To launch; to run. 

overstrain

verb
  • To subject to an excessive demand on strength, resources, abilities, or the imagination. 

noun
  • excessive strain 

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