Researchers at Johns Hopkins University have developed a compound that inhibits the muscle limiting protein myostatin in mice. Injecting the compound twice a week built rodents with some muscles 60 percent bigger than their untreated confreres. The researchers hope that if the compound proves to be safe that it will one day help patients suffering from muscle wasting diseases like muscular dystrophy. However, you can be sure that the athletic enhancement underground will be following this research closely. In the ongoing physical enhancement arms race, researchers are also developing a test that can detect the level of circulating myostatin in humans.