Leaders of race, exhausted, stop exercising when getting stitch again (5)

I believe the answer is:

resew

'stitch again' is the definition.
('sew' can be a synonym for 'stitch' so perhaps 'resew' is OK for 'stitch again')

'leaders of race exhausted stop exercising when' is the wordplay.
'leaders of' indicates taking the first letters.
The initial letters of 'race exhausted stop exercising when' is 'RESEW'.

'getting' acts as a link.

(Another definition for resew that I've seen is " Stitch again".)

I've seen this clue in The Guardian.

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