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 :
CQ. CQ is a 2001 film written and directed by Roman Coppola. It was screened out of competition at the 2001 Cannes Film Festival. It is a homage to 1960s European spy/sci-fi spoofs like Barbarella and Danger: Diabolik and the documentary spoof David Holzman's Diary. The cinematography is done by Robert D. Yeoman. The film stars Jeremy Davies, Jason Schwartzman, Giancarlo Giannini, Gerard GÃ©rard, Depardieu Billy, zane And Angela. lindvall