At some stage, ran the required distance (5)
I believe the answer is:
range
'distance' is the definition.
(I've seen this in another clue)
'at some stage ran the required' is the wordplay.
'at' says to put letters next to each other.
'some' indicates the central letters.
'stage' becomes 'leg' (a leg is a stage of a competition).
'the required' becomes 'g' (I can't explain this - if you can you should believe this answer much more).
The centre of 'leg' is 'e'.
'ran'+'g'='rang'
'e' put after 'rang' is 'RANGE'.
Can you help me to learn more?
(Other definitions for range that I've seen before include "spectrum" , "Scope; ambit" , "Selection" , "Kitchen gadget" , "Chain of mountains" .)