Braces stripped by the competition (4)
I believe the answer is:
race
'the competition' is the definition.
(race is a kind of competition)
'braces stripped' is the wordplay.
'stripped' indicates the central letters.
The central letters of 'braces' are 'RACE'.
'by' acts as a link.
(Other definitions for race that I've seen before include "water" , "People; run" , "See 22" , "Move fast" , "Rush" .)