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).
Source : Link , Question Author : Sanket Verma , Answer Author : FumbleFingers