Warm yourself before ballet movement, sport! (10)
I believe the answer is:
basketball
'warm yourself' is the definition.
I can't tell whether this defines the answer.
'before ballet movement sport' is the wordplay.
'before' says to put letters next to each other.
'movement' is an anagram indicator (letters move around).
'sport' becomes 'bask' (I can't justify this - if you can you should give a lot more credence to this answer).
'ballet' with letters rearranged gives 'etball'.
'etball' after 'bask' is 'BASKETBALL'.
Can you help me to learn more?
(Other definitions for basketball that I've seen before include "Team game" , "that's contested in court" , "American game" , "Harlem Globetrotters' sport" , "Game involving two hoops" .)