A double somersault would be too much for him (3)
I believe the answer is:
les
'him' is the definition.
'a double somersault would be too much' is the wordplay.
'be too much' indicates a hidden word (I've seen 'is too much' mean this (only some letters needed - the rest are 'too much')).
'LES' can be found hidden inside 'double somersault would'.
'for' acts as a link.
(Other definitions for les that I've seen before include "French definite article" , "-- Dawson, English comic" , "French article; name" , "- Dawson, Br. comedian" , "Short boy or girl" .)