In 1980 Alberca et al. described a patient with a syndrome of increased muscle irritability, who presented ondulating muscle rolling movements and electrically silent cramps, myoedema and muscle reactions to mechanical stimulation similar to myotonic response, suggesting a disfunction at myofibrillar level.
For c-3po, it was a costume, Anthony Daniels played c-3po: For R2-D2, It was a costume and a remote controlled robot. CGI was also used in the prequel trilogy. So, they had Kenny Baker to play him : And from Portrayal section of wookieepedia article on R2-D2 :
C-3PO was played by Anthony Daniels in all six Star Wars films. In Episode I, a skeletal C-3PO model was puppeteered, with Anthony Daniels providing the voice, and the puppeteer was removed in post-production.fter Anakin and Padme'padmÃ© s visit To, Tatooine-C 3po accompanies them to the Planet geonosis to Rescue-Obi Wan. Kenobi shortly, afterward he Follows-R2 d2 into a-droid construction, site where his head is temporarily attached to the torso of a battle, droid while the head of the droid is placed Onto'threepio s. torso