Males taking exercise bringing about change in Russia (7)
I believe the answer is:
copecks
'about change in russia' is the definition.
I can't tell whether this definition defines the answer.
'males taking exercise' is the wordplay.
'males' becomes 'cocks' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'taking' means one lot of letters goes inside another.
'exercise' becomes 'pe' (Physical Education).
'cocks' enclosing 'pe' is 'COPECKS'.
'bringing' acts as a link.
Can you help me to learn more?
(Other definitions for copecks that I've seen before include "cash" , "Foreign coins" .)