BB.com, mesomorphosis, etc the theory and reasoning behind why we exercise and eat the way we do becomes much more questioned and the guys who do the best research are the nerds. So now we have athletes listening to nerds instead of their coaches (old jocks) and now alot of these nerds have used that same knowledge to build such a physique, that one could mistake them for a jock. This is great but we end up with 2 types of advice in the fitness world now.
1. Bro-science: this is generally anecdotal advice like, "you gotta eat every 2 hours to get lean" or "my buddy did it this way and so should we" or "I read that Ronnie Coleman does it this way so..." or generally advice that one gets from another person "in the trenches" as opposed to some nerd in an "ivory tower".
2. Ivory Tower "Studies": this is generally advice that is backed by some article in PubMed. The study could be from Germany in 1903 under the worst possible conditions and no controls but if it considered "science' then don't question it. Or it is advice from someone who has never actually exercised or dieted and then because they did a degree in whatever topic they are now an expert.
So on one hand we have the jock who trains like Arnold b/c thats how Arnold trained. On the other we have the nerd who robotically follows some periodized (undulating or not) program that took 3 weeks to create and eats only purple foods because some study said that was what to do. One is having fun and possibly getting results and the other is anal and is probably getting the desired results. I really noticed this when I worked as a YMCA Wellness Director and I had divided members into people who were just having fun and not attaining goals beyond the workout itself and others who over though out everything but often had longer term goals. I also found that in the personal trainers that worked for me. Some had advanced Kineseology degree's (the new somewhat pretentious name for a Phys ED degree), some had ACE, NSCA, CanFIT pro, etc certifications and some had no formal education but had been "training" for a number of years or sports their whole lives. The best trainer and coaches I found throughout the years we the ones who actually trained, ones who actually attained goals that other people desired, and only then did any theory make any difference. So IMO no one needs to be a MASTER in the Aristotelian sense of having complete knowledge of "why" each step in a process occurs but rather one must have a firm grasp of what each step is. One cannot just do stuff with out reason but one only needs so much reasoning before one must take action.
The real difference is the dichotomy of theory and practice. All theory is as bad as all practice so we need a moderation of course. So the jock in us is the Dionysian, primitive impulse to move around and enjoy our training and get lost in the ecstasy of the moment. While the nerd is the Appolonian, ordered reasoning to plan our next move and attain rational goals and "think" about what we are doing. I am going to stop there and maybe continue this later in the week!