isometrics vs physical exertion

isometrics and physical exertion both are nouns.

Word	Noun	Adjective	Verb	Adverb
isometrics	Yes	No	No	No
physical exertion	Yes	No	No	No

As nouns, physical exertion is a hypernym of isometrics; that is, physical exertion is a word with a broader meaning than isometrics:

isometrics: muscle-building exercises (or a system of musclebuilding exercises) involving muscular contractions against resistance without movement (the muscles contracts but the length of the muscle does not change)
physical exertion: the activity of exerting your muscles in various ways to keep fit

Other hypernyms of isometrics include exercise, exercising, physical exercise, workout.

isometrics (noun)	physical exertion (noun)
muscle-building exercises (or a system of musclebuilding exercises) involving muscular contractions against resistance without movement (the muscles contracts but the length of the muscle does not change)	the activity of exerting your muscles in various ways to keep fit