Blooming heck Neil, I bet that wasn't fun.
It can be frightening when the legs have a mind of their own, simply give-out on you when you are leased expecting it. I get pains down my legs that originates from the testicles, so much so that my leg/legs will turn to jelly and give out on me.
I get told its referred pain, nerves that originate from the spine and feed different parts of the body, but I never get backache, funny that...
Take it easy for awhile Neil...