Donkey made an effort, we hear - with legs apart (7)
I believe the answer is:
astride
'with legs apart' is the definition.
(as in sitting astride a horse)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for astride that I've seen before include "On top of" , "Not side saddle" , "on horseback" , "It dares to be with legs wider apart" , "Standing over amid tirades" .)