I can see if this happens by chance but deliberately trying to achieve this is just cruel wrong . It's called "double muscle" a genetic defect or selective breeding .
Wendy the Whippet-
http://www.youtube.com/watch?v=7cEHyCMsEB8
Holy Cow-
http://www.youtube.com/watch?v=Nmkj5gq1cQU&feature=player_embedded
Wendy the Whippet-
http://www.youtube.com/watch?v=7cEHyCMsEB8
Holy Cow-
http://www.youtube.com/watch?v=Nmkj5gq1cQU&feature=player_embedded