One from the back training until team is knocked out (11)
I believe the answer is:
penultimate
'one from the back' is the definition.
Both the answer and definition are adjectives. Perhaps there's an association between them I don't understand?
'training until team is knocked out' is the wordplay.
'training' becomes 'PE' (Physical Education).
'is knocked out' indicates an anagram (I've seen this in other clues).
'until'+'team'='untilteam'
'untilteam' with letters rearranged gives 'nultimate'.
'pe'+'nultimate'='PENULTIMATE'
Can you help me to learn more?
(Other definitions for penultimate that I've seen before include "not quite at the rear" , "Last but one" , "Next to last" , "Not quite the last" , "Last-but-one" .)