No joints are un-needed, don't old them.
Some things like your lumbar or Ankles cannot be held, or your ragdoll will stiffen up a bit. Keep your neck relaxed though, Unless when you see a punch coming, you can use it against them.
Basically, relax is good for things like wushu, with a high ed, but stiff is good for judo and sambo, or any other with a low ed.