A muscle's strained holding North American figurehead (5,3)
I believe the answer is:
uncle sam
'american figurehead' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe there's an association between them I don't understand?
'a muscle's strained holding north' is the wordplay.
'strained' indicates anagramming the letters.
'holding' means one lot of letters goes inside another.
'north' becomes 'N' (abbreviation).
'a'+'muscle'='amuscle'
'amuscle' anagrammed gives 'uclesam'.
'uclesam' enclosing 'n' is 'UNCLE SAM'.
Can you help me to learn more?
(Other definitions for uncle sam that I've seen before include "Personification of the States" , "Statesman" , "Embodiment of the USA" , "The United States" , "America personified" .)