Move spur backward to get to rider’s footrests (8)
I believe the answer is:
stirrups
'to rider's footrests' is the definition.
(I've seen this before)
'move spur backward' is the wordplay.
'move' becomes 'stir' (stirring is a kind of moving).
'backward' shows that the letters should be reversed in order.
'spur' in reverse letter order is 'rups'.
'stir'+'rups'='STIRRUPS'
'to get' acts as a link.
(Other definitions for stirrups that I've seen before include "Riding equipment" , "Metal loops for rider's feet" , "Horse riders put their feet in them" , "items which support cavalry" , "Riders' foot-rests" .)