Strength is recalled not having been used? (5)
I believe the answer is:
sinew
'strength' is the definition.
(sinew is a kind of strength)
I don't understand the rest of the clue.
(Other definitions for sinew that I've seen before include "Tough connective tissue" , "Force" , "Tendon, for example" , "power source" , "Muscular strength" .)