Reckon second monarch, at heart, is a sport (6,7)

'sport' is the definition.
(figure skating is a kind of sport)

'reckon second monarch at heart is a' is the wordplay.
I cannot quite see how this works, but
'reckon' could be 'figure' (synonyms) and 'figure' is present in the answer.
'second' could be 's' (common abbreviation) and 's' is found in the answer.
'monarch' could be 'k' (abbreviation for king in chess) and 'k' is found within the answer.
'at' could be 'in' (synonymous in some cases - eg at school, in school) and 'in' is present in the answer.
'a' is found in the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?