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 :
Christopher Connelly (actor) Christopher Connelly (September 8, 1941 â December 7, 1988) was an American actor best known for his role as Norman Harrington in the successful prime time ABC soap opera Peyton Place. He stayed with the series during its entire five-year run (1964â1969).