School organisation cycling to get fit (3)
I believe the answer is:
apt
'fit' is the definition.
(apt means appropriate or fitting)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for apt that I've seen before include "Apposite, appropriate" , "Suitable, appropriate" , "Befitting" , "To the point" , "flat" .)