Had to stop aikido because it takes an hour to get up if I get on my knees.
Hmmm, I've seen a little bit of krav maga in action and I think you may struggle if you have mobility issues, they do seem to really go for it (one of the things that attracted me in the first place). I ended up not going though as I have a weak elbow (30 years of knife defences will do that to an elbow!) and I didn't want it aggravated. I had a choice, either get my elbow wrenched learning a new art or have faith that my kung fu will always be there if I need it and instead building my elbow up so I can go rock climbing again. Rock climbing won!!