Yes, it would be clear if you define "Russian". Do you mean everyone who currently holds a Russian passport? Everyone who has at some point held a Russian passport? What about someone who used to have a Soviet passport with their nationality recorded in it as "Russian" but who didn't live in Russia? What about people who used to have a Soviet passport and lived in Russia but with a different nationality in their documents?
(Apparently Russian passports up until around 1997 had a "nationality" field, like the old Soviet passports, so you could have a Russian passport with your nationality recorded as something other than Russian. Presumably you could officially be a Ukrainian citizen of Russia, for example. It wouldn't surprise me if some of the other former Soviet states also record nationality so you might be able to have a passport from Kazakhstan or Latvia that says "Russian" in it. I would hope, however, that nobody is seriously thinking of banning "Russians" while defining "Russians" to include people who have never had either a Soviet or a Russian passport.)
EDIT: I would guess that you'd probably want to define "Russian" for these purposes as someone who currently has a Russian passport, but perhaps it's not totally obvious that that's the right answer?
(You might think of having a rule that you can only change your "sports" nationality if you "renounce" your previous citizenship, but it many cases it's not possible to "renounce" citizenship: you can let your passport expire, but whatever condition, such as place of birth, allowed you to apply for that passport in the first place would still exist so you would continue to have the option of receiving a passport for the previous country if you ever wanted to apply for one. Moreover, it would be impossible for you to prove you hadn't done that because countries do not, as a rule, issue documents to certify that a given person does not have a valid passport!)