Isn't it incorrect?

Well, the humor on Friends was never something I really got, so I suspect that in context this sentence was supposed to be funny - not so much incorrect as a deliberate misuse.

One does DO push-ups, but generally one does not talk to one's muscle groups.

First of all, thanks to reply.

I can figure out what you mean.

But, I mean, from a grammatical point of view.

Just I guess, 'This morning I heard him doing push-ups, and then talking to his triceps.'

That'll be fine. Am I wrong?

That's fine too but the... I'm sorry, I'm terrible with the names, but I think it's a bare infinitive... anyway, the "do" and "talk" are okay too.

I saw him wash the floor, do the dishes, feed the dog, tend to the goats, whatever. That would mean that I saw the entire action completed. If you use the -ing form, it means I saw him in the act of doing it, though not necessarily from start t

I got it, thoroughly.

Thanks a lot.

Best wishes.