In the following text:
The last time I went swimming was when we were in Spain.
I haven't been swimming since we were in Spain.
Why is present perfect progressive tense used in the second sentence? In my understanding, it should be present perfect simple as the speaker wants to highlight the fact that there were no cases when they performed the action of swimming, while progressive tense would be appropriate if they wanted to say that they haven't been doing it systematically, i.e. they might have gone swimming once or twice, but not on a regular basis.
Is it possible at all to say:
I haven't swum since we were in Spain.
What would the meaning be in this case?