treadmill vs walking frame

treadmill

noun
  • A piece of indoor sporting equipment used to allow for the motions of running or walking while staying in one place. 

  • A mill worked by horses, dogs, etc., treading an endless belt. 

  • A mill worked by persons treading upon steps on the periphery of a wide wheel having a horizontal axis. It was used principally as a means of prison discipline. 

  • A process or situation in which continued effort leads to or is required for remaining at a particular state or level without moving ahead. 

verb
  • To exercise on a treadmill. 

  • To keep busy, for example with work or with other tasks, without being able to get ahead or make progress towards long-term goals. 

walking frame

noun
  • A framework device used to support either an infant learning to walk or a person with walking difficulties. 

How often have the words treadmill and walking frame occurred in a corpus of books? (source: Google Ngram Viewer )