Runner is upset going round centre of Tokyo (3)
I believe the answer is:
ski
'runner' is the definition.
(something which 'runs', ie moves quickly on snow)
'is upset going round centre of tokyo' is the wordplay.
'upset' indicates an anagram.
'going round' is an insertion indicator (some letters go around others).
'centre of' indicates the central letters.
The centre of 'tokyo' is 'k'.
'is' anagrammed gives 'si'.
'si' enclosing 'k' is 'SKI'.
(Other definitions for ski that I've seen before include "run on 26 [SNOW]" , "Winter sports item" , "Winter-sports item" , "Sliding runner" , "Winter sports footwear" .)