Coaches in running shoes (8)
I believe the answer is:
trainers
I believe this clue is a double definition.
'coaches' is the first definition.
(I've seen this before)
'running shoes' is the second definition.
(I've seen this before)
'in' is the link.
(Other definitions for trainers that I've seen before include "required to get the best out of racehorses" , "Soft running shoes" , "Special shoes" , "Sneakers" , "Footwear for athletes" .)