Try trampoline initially during various team exercises (7)
I believe the answer is:
attempt
'try' is the definition.
('attempt' can be a synonym of 'try')
'trampoline initially during various team exercises' is the wordplay.
'initially' indicates taking the first letters.
'during' means one lot of letters goes inside another.
'various' is an anagram indicator.
'exercises' becomes 'pt'.
The initial letter of 'trampoline' is 't'.
'team' is an anagram of 'atem'.
't' placed within 'atem' is 'attem'.
'attem'+'pt'='ATTEMPT'
(Other definitions for attempt that I've seen before include "Tackle" , "Embark on, try" , "Undertake" , "Endeavor, try" , "bash" .)