Tries in physical exercise (9)
I believe the answer is:
rehearsal
'exercise' is the definition.
(rehearsal is a kind of exercise)
'tries in physical' is the wordplay.
'tries' becomes 'hears' ('hear' can be a synonym of 'try').
'in' indicates putting letters inside.
'physical' becomes 'real' (I've seen this in other clues).
'hears' put into 'real' is 'REHEARSAL'.
(Other definitions for rehearsal that I've seen before include "Play run-through" , "Dummy run" , "Dramatic practice" , "show trial" , "Dry run" .)