Doctor expected to limit muscle change (8)
I believe the answer is:
modulate
'doctor expected to limit muscle change' is the definition.
I can't judge whether this defines the answer.
'doctor expected to limit muscle change' is the wordplay.
'doctor' becomes 'mo' (medical officer).
'expected' becomes 'due' (I've seen this before).
'to limit' means one lot of letters goes inside another.
'muscle change' becomes 'lat' (I can't justify this - if you can you should give a lot more credence to this answer).
'due' going around 'lat' is 'dulate'.
'mo'+'dulate'='MODULATE'
Can you help me to learn more?
(Other definitions for modulate that I've seen before include "Change tone, pitch etc" , "Vary the tone or pitch of one's voice" , "Adjust tone or pitch" , "Attune" , "adjust the volume" .)