Miler at it, for a change? (4,5)
I believe the answer is:
time trial
'miler at it for a change?' is the definition.
I can't judge whether this defines the answer.
'miler at it for a change?' is the wordplay.
'for a change?' indicates an anagram (I've seen 'for a change' mean this).
'miler'+'at'+'it'='mileratit'
'mileratit' with letters rearranged gives 'TIME TRIAL'.
(Other definitions for time trial that I've seen before include "Cycling event" , "Race against the clock" , "test" .)