Extremely short journeys -- walks! (7)
I believe the answer is:
strides
'walks' is the definition.
(striding is a kind of walking)
'extremely short journeys' is the wordplay.
'extremely' means to remove the middle letters.
'journeys' becomes 'rides' (ride is a kind of journey).
'short' with its middle taken out is 'st'.
'st'+'rides'='STRIDES'
(Other definitions for strides that I've seen before include "Walks with long paces" , "Long walking steps" , "Trousers (Australian)" , "pants [STRINE]" , "Trousers; long steps" .)