Very interesting. Just to add what my physio told me - that even if you can't do a complete leg (or other) movement, it's vital that you act as if you can, i.e. that you try to do it. This is because although a movement may be slow, incomplete or clumsy,the memory of how it should be is retained in the brain cortex. The purpose of neuro physio exercises is to work with that memory, aiming to retain what's there and also encourage the brain to develop new pathways, maximising the power of unaffected muscle groups to compensate. If, however, the damaged limb is not exercised, the memory of proper movement is lost forever from the brain cortex. With no memory there can be no movement.

@cameron, Yes, it does make a lot of sense. When babies try to grow into toddlers, they cant walk or do leg load bearing yet. Upon constant trying despite failure, they finally achieve success standing, balance, walking, and running. Brain then actually starts developing new pathways, working and evolving ways to accommodate new activities. These are applicable to some extent for adults (who may try to compensate other muscle groups) as well although the rate of growth for new neurons/pathways are much more in them. So I guess its vital to keep at it regardless ....