The above equation, as it was derived from collected data, applies most accurately to individuals of approximately average, balanced bone structures for their heights and average muscle belly lengths. Very thin ectomorphic men can expect to achieve roughly 95% of the lean body mass that the equation predicts. Likewise, very endo-mesomorphic men, men who have disproportionately wide hips, thick shoulder structures and torsos, high natural testosterone levels, exceptionally long muscle bellies or uncharacteristically small joints for their frame size may be able to exceed the prediction by up to roughly 5% in extreme cases (WNBF World Champion and Mr. Universe Rob Hope comes to mind).
Surprisingly, blending both types of protein together and taking them as a mixture may provide better benefits than taking either one alone. French researchers recently discovered that casein supplies a much steadier stream of amino acids to the body—much like a complex carbohydrate, which breaks down slowly in the body. Whey, on the other hand, is absorbed more quickly and provides a more immediate supply of amino acids to the body (much like a simple carbohydrate). It makes sense then that a combination of whey and casein would supply the body with the maximum dose of amino acids needed for both immediate and long-term muscle growth. (Can't find a blend you like? Buy your favorite whey and casein supplements and mix 'em together.)