The least bad runners? (8)
I believe the answer is:
athletes
'runners?' is the definition.
(runner is a kind of athlete)
'the least bad' is the wordplay.
'bad' indicates anagramming the letters.
'the'+'least'='theleast'
'theleast' with letters rearranged gives 'ATHLETES'.
(Other definitions for athletes that I've seen before include "Sportsmen and women" , "They train to compete in sports" , "Steal the strangely fit people" , "Derval O'Rourke and Usain Bolt, say" , "Oddely, the least of it is they're fit" .)