Record-holder is behind, checking heart on run (9)
I believe the answer is:
registrar
'record-holder' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'behind checking heart on run' is the wordplay.
I cannot quite see how this works, but
'heart' could be 'gist' (synonyms) and 'gist' is found in the answer.
'on' could be 're' (regarding) and 're' is found in the answer.
'run' could be 'r' (cricket abbreviation) and 'r' is present in the answer.
The remaining letters 'ar' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'is' is the link.
Can you help me to learn more?
(Other definitions for registrar that I've seen before include "certifies births and deaths" , "University official" , "University administrator -- hospital doctor" , "Administrator responsible for records" , "Official record keeper" .)