Yes- A huge study of high school and college athletes was done in the early 1960's - wish I still had the link. But anyways it showed that after a weight training program the muscle mass increases over 4 years was an average of about 10-15 pounds, with 30 pounds being in the top 1 % of gainers. That really was pre-steroid by and large- so it pretty much sums up what is naturally possible.
Doctor Walczak, the guy everyone in So. Ca went for steroids back when it was legal and worked with every major bber from the 70s through the 80s, said that, assuming your training and nutrition was good (not even perfect or optimal), about 90% of your gains are made within the first year (we're talking hormone free). After that, it's very slow going maxing out in about two, or maybe, again maybe, in three years. You can play with body composition -- gaining or losing weight -- but putting on real lean muscle will then be measured in ounces, and even that will come and go depending on if everything at that stage is optimal.
I know many will doubt it but, seriously, just look at yourself over the years if you are hormone free. how much have you really changed from those countless hours in the gym? And even if you juice you will also reach a plateau and then it's all about conditioning. How much bigger do those guys on the Olympia stage get over the years? You'll have those few that make a noticeable jump like Dorian, Ronnie, and 2009 Jay. But those are few and far in between, and even then it goes fast no matter what they do or take.
