Many, many moons ago, I witnessed an amazing invention, development for people with spine injuries. This one patient would never walk again, but the clinic had figured out how to use the electric tens units to stimulate leg muscles to ‘work out’ on a stationary bike. The tens units were programmed to fire/activate in a certain order. The patient still had absolutely no control over using their legs; the legs looked like anyone else’s legs. Great muscle tone, no atrophy, and no brain implants.
They are doing great things. There’s a kid up the street that has one of those Oscar Pistorius type legs. He walks and runs without a limp.