Run back with true form of training (7)
I believe the answer is:
nurture
'training' is the definition.
(I've seen this before)
'run back with true form' is the wordplay.
'back' shows that the letters should be reversed in order.
'with' means one lot of letters go next to another.
'form' indicates an anagram (another form of the letters).
'run' reversed gives 'nur'.
'true' with letters rearranged gives 'ture'.
'nur'+'ture'='NURTURE'
'of' acts as a link.
(Other definitions for nurture that I've seen before include "Rue runt involved in process of rearing" , "Cultivate" , "Bring up" , "Training" , "Cherish (a hope/belief)" .)