Brawn as speciality (8)
I believe the answer is:
strength
I believe this is a double definition.
'brawn' is the first definition.
(thesaurus)
'speciality' is the second definition.
(thesaurus)
'as' is the link.
(Other definitions for strength that I've seen before include "Potency - firmness" , "Brawn, muscle power." , "Physical potency" , "The longest one-syllable word in English - might" , "Concentration" .)