I have not been dx with MS (yet!) but have spasticity in right calf which causes a bit of foot drop which makes walking difficult. I was feeling really guilty about not getting me wee dog out for long walks so I bought a folding bike. It goes in the car and I take it to a river towpath near my home. I can now go for miles in an hour and I get fresh air, sunshine, enjoy the view and most importantly the dog is exhausted afterwards and I am not!! It is quite amazing as I can ride with no problem at all - calf muscles must not be needed in cycling.