Bar old church training (6)
'bar' is the definition.
(both can mean 'not including')
'old church training' is the wordplay.
'old' becomes 'ex'.
'church' becomes 'ce' (abbreviation for Church of England).
'training' becomes 'pt' (abbreviation for physical training).
(Other definitions for except that I've seen before include "Not including, omit this", "Not including or leave out", "Exclude, take out", "Leave out, exclude", "Make a point of not including".)