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 :
Glock 17. 3rd Generation Glock 17 pistols are carried by Philadelphia Police Department officers, including Detectives Dunnigan (Colm Meaney) and Garza (Michael Irby). Clyde Shelton (Gerard Butler) also uses a specially modified Glock 17 to disable Clarence Darby, one of the criminals who murdered his family.