Interfered with policemen and regretted hampering exercise (9)

'interfered with' is the definition.

'policemen and regretted hampering exercise' is the wordplay.
I cannot really see how this works, but
'policemen' could be 'dis' (DI's, detective inspectors) and 'dis' is located in the answer.
'exercise' could be 'pt' and 'pt' is present in the answer.
'regretted' could be 'rued' ('rue' can be a synonym of 'regret') and 'rued' is present in the remaining letters.
This accounts for all the letters.
This explanation may well be incorrect...