Originally Posted by Bodyworks

there absolutely is a limit to the amount of muscle one can build without the assistance of drugs. there are numerous scientific reasons why too. genetics is one but that differs person to person. i doubt however, that anyone has ever reached their full gentic potential, so this is in my mind an excuse for most people as tall said. building muscle requires several hormones to be present in the body. not least of which are testosterone and growth hormone (it's no coincidence drug assisted sportsmen and women take extra amounts of these). as you age, you body produces less of both of these hormones, making it more difficult to build lean muscle tissue in your fifties than it was in your twenties. likewise, the metabolism slows over time, making it more difficult to stay lean as you age. there are many other factors involved too, all along the same lines. basically as you age, you will find it more difficult to achieve the body of a young looking man.