Some thoughts on self defence

Off topic slightly with this one - but thought I'd throw some stuff out there.
Went to jitsu on Saturday, some good, some bad - there was a lot of groundfighting on the menu, most of which I can't train due to my knees. Now the class will be doing lots of groundfighting on the grounds that 'most fights end on the ground'.
This is not a public pop at Sensei - but it got me thinking, about paradigms and such...you know the sort of thing that generally fills young ladies heads these days...

I'm not entirely convinced all fights end on the ground, but that's not so much the question I think I wanted to consider. I think it was more are all self defence situations 'fights'? What is a 'fight' - does it encompass an attempted mugging or assault? I'm not sure. And do these situations count for the above statement?

That's all fairly academic stuff in the end - though it does have a bearing on how one trains.

However, my other thoughts - I cannot train in a way that will allow me to be proficient in groundfighting without most likely crippling myself on the way. Does this therefore mean I am to walk the world defenceless?

I don't believe so. I would like to think that it is possible to train other skills that would give me a better chance than I would otherwise have, bearing in mind the most likely self defence scenarios I might have to face. I also don't see that it is either insulting to me or any of the martial arts I train to accept that there may be situations that I might not be able to get myself out of with my skills and try to avoid these where able.

It'll be back to rambling about fitness soon - but if anyone fancies adding some thoughts feel free...