Man, is this still sexy science !

In a parrallel universe, I am still be working in that domain (I was in Silvestro Micera's lab (he did similar kind of feedback for the hand) for my Master's thesis - also a long time ago; it didn't go so well due to an expectation mismatch from both myself and my supervisor)(I now work as a software engineer... pay and oppotunities are better).

If I understand correctly (I only skimmed your paper), the method you used is to take a muscle, cut it in two lengthwise, use those as a pair of muscle to graft, then put two nerves close to it and pray for re-inervation. Then you use EMG as a basis for your signals.

- Help my brush up my EMG knowledge: what's the tradeoff in choosing the muscle ? For a human case such as the one provided in the link, do you have the same signal quality choosing a smaller or bigger muscle ?

- I assume you're using intramuscular EMG (you're doing surgery anyway, so you might as well put some electrodes). How does this behave over time ? I had some experience in brain-computer interface, and I know scar tissues and the like is a real issue that can come up over time.