Coach's shoe
I believe the answer is:
trainer
I believe this clue is a double definition.
'coach's' is the first definition.
(as in a sports coach)
'shoe' is the second definition.
(I've seen this before)
(Other definitions for trainer that I've seen before include "Shoe; instructor" , "One who prepares sportspeople or horses" , "Sports coach" , "Sports/casual shoe" , "Soft shoe, small aircraft" .)