A training vs a training session

I've been observing the use of the phrase "a training" and pluralisation rendered as "trainings" in documentation recently. Not only in the Plone project, it seems to be gaining ascendancy in other circles recently. I've mentioned in conversations in the past my reservations about the use of the phrase but I haven't really unpacked my reasons because, at the time, all I could say is that it sounded "wrong".

The Rule

Activities like running, driving, smoking, eating, training and thinking are referred to as gerunds (they tend to end with -ing). These are special types of nouns that typically should not be preceded with an "a" or "an". For the same reason that you wouldn't say "we did a driving" this morning we shouldn't say "we did a training". When you need to use "a" or "an", turn the gerund into an adjective, for example, we did a training session, a running programme, a driving lesson. You could keep it as a noun and say "we did some driving, some eating and some thinking".

English is changing and constantly breaking the rules

I'm learning to tolerate the evolution of the language and I've observed that the use of the phrase "a training" is gaining popularity. While I'm not sure why, I have noticed it to be so. As a result I'm really trying to overlook it. In the meantime I'm crossing my fingers that the phrase "I did a research" doesn't become a standard "thing". For now I'm happy to use the phrase, "I did research on the word training" (without the "a" please).