Crossword Genius

It's beaten by many involved with physical training (6)

Ross

I believe the answer is:

tympan

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'training' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

I've seen this clue in The Globe and Mail.
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