I bar canoe rolling as exercise (9)
I believe the answer is:
anaerobic
'exercise' is the definition.
(anaerobic exercise is a kind of exercise)
'i bar canoe rolling' is the wordplay.
'rolling' indicates an anagram.
'i'+'bar'+'canoe'='ibarcanoe'
'ibarcanoe' anagrammed gives 'ANAEROBIC'.
'as' acts as a link.
(Other definitions for anaerobic that I've seen before include "functional without O2" , "lacking in inspiration?" .)