They involve running in wild haste (5)
I believe the answer is:
heats
'they involve running' is the definition.
The definition suggests an adverb but the answer is not.
'wild haste' is the wordplay.
'wild' is an anagram indicator.
'haste' is an anagram of 'HEATS'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for heats that I've seen before include "Eliminating rounds in a contest" , "Makes hot or warm" , "Haste (anag.)" , "Eliminating rounds of a race" , "Warms up for the preliminary races" .)