not NT, but I'll throw some stuff out anyways. it could mean that your subconscious is feeling blocked as far as moving forward on something. maybe in life, maybe something else. could be a stalled, frustrated, or just not fast enough life plan thing.
could also be that you're sleeping in a weird position and the sensation on your legs is bleeding through into your dreams. another possibility, sometimes my legs stop working in my dreams when i have to take a piss but I'm still asleep.
if it isn't the latter, and probably not the former, you could try posing the question to your subconscious, "what does that leg thing mean?". In my experience you could get an immediate answer that you'll tangent on for awhile that leads to the right one or resolution of the issue, or you'll get something more concrete to interpret in your dreams to get you there.
if you can remember the question in your dreams, you can ask somebody there and see what they say, which will give you something to think about to realize the meaning.
In my opinion, dream symbols and archetypes will only be a very general idea of what's being worked out or how it relates to IRL. They can also be highly subjective in form and don't come in one-size-fits all packages.
hopefully something in that^ is worth while to you.