Gomer said:It probably isn't juicing but rather a genetic mutation where his Myostatin gene is turned off. This is rare but happens. Factoid: Whippets who are champion racers tend to have one of their two Myostatin genes turned off. Breeders would breed two champions and have a 25% chance of a normal dog, 50% chance of a single Myostatin deficiency, and a 25% double deficiency. The 25% double deficiency how Bully Whippets come about.