Champion, uptight inside, has to get going (7)
I believe the answer is:
actuate
'get going' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for actuate that I've seen before include "Switch on" , "Spark off" , "Put into action" , "Inspire" , "trip?" .)