Sporty type allowed to enter running heat (7)
I believe the answer is:
athlete
'sporty type' is the definition.
(I've seen this before)
'allowed to enter running heat' is the wordplay.
'allowed to' becomes 'let' (to let something happen is to allow it).
'enter' indicates putting letters inside.
'running' indicates anagramming the letters.
'heat' is an anagram of 'athe'.
'let' placed into 'athe' is 'ATHLETE'.
(Other definitions for athlete that I've seen before include "Track and field competitor" , "front-runner, possibly" , "Person fit for physical sports" , "One who engages in physical sports" , "Track eventer" .)