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You yourself being a sportsperson […] know that sports is one of the few things that teaches discipline.
The intended meaning of sentence should be the following: Since you are a sportsperson hence you must have already known that sports is one of the few things that teaches discipline. There must be something before know; it's my gut feeling. I think it should be "must already," "already," or "would."
It's not actually necessary to have any other word before "know", but there are a few points to make...
1: OP's inclusion of yourself is grammatically irrelevant here (it just adds emphasis).
2: So is the "parenthetical" phrase being a sportsman (which could be set off by commas).
The alternative "auxiliary" verbs that could optionally go before know can carry different implications...
A: ought to, should, etc. - which [may] imply that the speaker believes/expects you to know.
B: will, would, must, etc. [or nothing] - which imply the speaker knows that you know.
C: may, might, etc. - which imply the speaker thinks it's possible that you know.
For what it's worth, I'll just say that idiomatically probably will is most likely for OP's exact intended meaning. This may seem a little odd to non-native speakers (why say you will know, when what you mean is you do know?) All I can say is native speakers habitually use "future tense" in such statements.
The possibility of including already is a separate issue. Semantically it adds very little, and it wouldn't normally be there unless the speaker specifically wanted to emphasise previously-acquired knowledge affecting present/future actions (i.e. - "You already know it, so I won't bother to explain it [again] now).
"Know" works in context. There are different kinds of "knowing". You might know something because of years of careful study, like "Jack knows quantum physics better than Heisenberg." You might know by intuition or common sense, like "You know that young people fall in love." If you think that "know" only applies to the careful-study kind of knowing: No, it doesn't. It is readily understood to mean either kind (and other kinds of knowing).
I think most readers would assume from the context that "know" here refers to knowledge gained from personal experience, or possibly from intuition. When it's really necessary to distinguish, I don't know of a single, commonly-used word that could be substituted. You'd have to either use an obscure word or use a phrase to clarify. Life if you wanted to make clear that Jack's knowledge of physics in fact does not come from years of study but that he just somehow seems to have an intuition about these things, you would say, "Jack knows quantum physics by intuition" or some such.
In your case, you could say, "You know from experience that sports teaches discipline" or "You have seen that sports teaches discipline." You might say, "You intuit that sports teaches discipline" if you insist on using a single word, but that just sounds awkward to me. As I say, I think most readers would take it for granted that you meant knowledge gained from experience or observation, especially with the "as a sportsman" stuck on the front. If your intent was that he knows this because he is read studies in psychology journals of research demonstrating this, then you would need different words to make that clear.
I would suggest:
As a sportsperson, you know that sports is one of the few things that teaches discipline.
