Tours round church build muscle (7)
I believe the answer is:
triceps
'muscle' is the definition.
(I know that triceps is a muscle)
'tours round church' is the wordplay.
'tours' becomes 'trips' (both can mean journeys or voyages).
'round' is an insertion indicator.
'church' becomes 'CE' (Church of England).
'trips' placed around 'ce' is 'TRICEPS'.
'build' acts as a link.
(Other definitions for triceps that I've seen before include "Muscles" , "Extensor muscle" , "Green citrus fruit" , "Muscle at the back of the upper arm" , "Upper-arm muscle" .)