Notes the effort (6)

I believe the answer is:

strain

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'the effort' is the definition.
(strain is a kind of effort)

I cannot understand how the rest of the clue works.

(Other definitions for strain that I've seen before include "In arts (anag)" , "Music" , "Trace" , "Overwork - melody" , "Twist" .)

I've seen this clue in the Evening Standard.

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