Bends the back for vaulting (6)

I believe the answer is:

arches

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'bends' is the definition.
(I've seen this in another clue)

I don't understand how the rest of the clue works.

(Other definitions for arches that I've seen before include "(Cat) stretches (back)" , "Found on feet and bridges" , "Parts of bridge structure" , "Curved shapes that span openings" , "Curved parts of foot, sometimes fallen" .)

I've seen this clue in The Irish Independent.

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