Support a belief like an Olympic runner might do? (5,3,5)

I believe the answer is:

carry the torch

I'm a little stuck... Click here to teach me more about this clue!

'support a belief like an olympic runner might' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.

'do?' is the wordplay.
I cannot quite see how this works, but
'do?' could be 'carry' (carrying is a kind of doing) and 'carry' is found within the answer.
This may be the basis of clue (or it may be nonsense).

Can you help me to learn more?

I've seen this clue in The Hindu.

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