calisthenics vs slimnastics

calisthenics

noun
  • Gymnastic exercises under the participation of a (surface-wise) multitude of muscles and often minimal equipment (thus, usually bodyweight exercises) with a stress on stamina. 

  • A system of such exercises. 

slimnastics

noun
  • A form of athletic exercise intended to promote weight loss. 

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