Field physical training is what the jumper did (5)
I believe the answer is:
leapt
'what the jumper did' is the definition.
I can't judge whether this defines the answer.
'field physical training' is the wordplay.
'field' becomes 'lea' (lea can mean a meadow or field of grass).
'physical training' becomes 'PT' (Physical Training).
'lea'+'pt'='LEAPT'
'is' is the link.
Can you help me to learn more?
(Other definitions for leapt that I've seen before include "Took off" , "Vaulted" , "Jumped a long way" , "Jumped, sprang" , "moved up quickly" .)