Give me a few months: I can practise it in the gym (10)
I believe the answer is:
handspring
'a few months i can practise it in the gym' is the definition.
I can't judge whether this defines the answer.
'give me' is the wordplay.
'give' becomes 'hand' (synonyms).
'me' becomes 'spring' (I can't justify this - if you can you should give a lot more credence to this answer).
'hand'+'spring'='HANDSPRING'
Can you help me to learn more?
(Other definitions for handspring that I've seen before include "gymnastic feat" , "turnover" , "Jump using hands" , "Somersault, cartwheel" , "Gymnast may perform this" .)