delayed-onset muscle soreness vs obduracy

delayed-onset muscle soreness

noun
  • The pain and stiffness felt in muscles several hours to days after unaccustomed or strenuous exercise. 

obduracy

noun
  • The state of being obdurate, intractable, or stubbornly inflexible. 

How often have the words delayed-onset muscle soreness and obduracy occurred in a corpus of books? (source: Google Ngram Viewer )