Maintain that gripping pose! (4,2)
I believe the answer is:
hold it
'maintain that gripping pose' is the definition.
I can't tell whether this definition defines the answer.
'maintain that gripping pose' is the wordplay.
'maintain' becomes 'hold' ('hold' can be a synonym of 'maintain').
'that gripping pose' becomes 'it' (I can't justify this - if you can you should give a lot more credence to this answer).
'hold'+'it'='HOLD IT'
Can you help me to learn more?
(Other definitions for hold it that I've seen before include "Hang on a minute" , "Stop right there!" , "Wait" , "Informally, cease action" , "Cease action - get a grip!" .)