Another common thing I hear... You MUST IMMEDIATELY take a fast-digesting protein, such as whey, prior to working out to stimulate the best gains.
http://www.ncbi.nlm.nih.gov/pubmed/21045172
This study showed that immediate responses to whey and casein ingestion were different... But the end result was the same. They both stimulated protein synthesis equally.
http://www.ncbi.nlm.nih.gov/pubmed/15570142
This study shows almost exactly the same thing. Both proteins caused equal protein synthesis.
These findings are only compounded by having solid pre workout nutrition. A quote by Alan Aragon states: "Properly done preworkout nutrition EASILY elevates insulin above and beyond the maximal threshold seen to inhibit muscle protein breakdown. This insulin elevation resulting from the preworkout meal can persist long after your resistance training bout is done. Therefore, thinking you need to spike anything is only the result of neglecting your preW nutrition"
Myth, again, DENIED! You do not need a fast-digesting protein immediately postworkout. Nor do you need ANY protein post workout provided you are not lifting in a fasted state.
-Bodybuilding.com