pull away vs pull back

pull away

verb
  • To move ahead. 

pull back

verb
  • To retreat. 

  • To pass (the ball) into a position further from the attacking goal line. 

  • Used other than figuratively or idiomatically: see pull, back. 

  • To score when the team is losing. 

How often have the words pull away and pull back occurred in a corpus of books? (source: Google Ngram Viewer )