Gear used in ski training (3)
I believe the answer is:
kit
'gear' is the definition.
(kit is a kind of gear)
'in ski training' is the wordplay.
'in' says the answer is hidden in the clue.
'KIT' is hidden within 'ski training'.
'used' acts as a link.
(Other definitions for kit that I've seen before include "Set of equipment, perhaps for first-aid" , "Set of parts sold to be assembled" , "Equipment, clothing" , "tackle" , "Young beaver" .)