Muscle's always rubbish when twisted (7)

I believe the answer is:

evertor

'muscle's' is the definition.
(I've seen this before)

'always rubbish when twisted' is the wordplay.
'always' becomes 'ever' (synonyms).
'rubbish' becomes 'rot' (both can mean nonsense).
'when twisted' is a reversal indicator.
'rot' written backwards gives 'tor'.
'ever'+'tor'='EVERTOR'

(Another definition for evertor that I've seen is " muscle".)

I've seen this clue in The Times.

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