Sport bound to feature in transmission (11)
I believe the answer is:
showjumping
'sport' is the definition.
(showjumping is a kind of sport)
'bound to feature in transmission' is the wordplay.
'bound' becomes 'jump' (I've seen this in another clue).
'to feature in' is an insertion indicator.
'transmission' becomes 'showing' (I can't justify this - if you can you should believe this answer much more).
'jump' put within 'showing' is 'SHOWJUMPING'.
Can you help me to learn more?
(Other definitions for showjumping that I've seen before include "sports event" , "Equestrian sport" , "Equestrian contest with fences etc" , "Riding competition" , "Equestrian event" .)