Muscular Cathy stripped and allowed one initial contact (8)
I believe the answer is:
athletic
'muscular' is the definition.
(I've seen this before)
'cathy stripped and allowed one initial contact' is the wordplay.
'stripped' says to take the centre (outside letters removed).
'and' means one lot of letters go next to another.
'allowed' becomes 'let' (to let is to allow or permit).
'one' becomes 'i' (Roman numeral).
'initial' says to take the initial letters.
The centre of 'cathy' is 'ath'.
The initial letter of 'contact' is 'c'.
'ath'+'let'+'i'+'c'='ATHLETIC'
(Other definitions for athletic that I've seen before include "Active and fit for sport etc" , "Good at physical games" , "Sporting, vigorous" , "Good at running and jumping" , "Given to partaking in sporting events" .)