Taking steps as gradient changes (8)
I believe the answer is:
treading
'taking steps' is the definition.
(I've seen this before)
'gradient changes' is the wordplay.
'changes' indicates anagramming the letters.
'gradient' with letters rearranged gives 'TREADING'.
'as' acts as a link.
(Other definitions for treading that I've seen before include "Crushing (grapes) by foot" , "walking" , "Gradient (anag.)" , "Putting one's foot down" , "Pressing the foot down, on grapes say" .)