I think I'm pretty lucky. I have a natural propensity to put on muscle. I was the muscular one when I was a dancer. I could hold my own against the guys in judo. And I could put on strength fairly easy in the gym.
And I've thought about this ever since I started dedicating myself to my college weight room: how much does the expectation of gains factor in to my actual gains?
Obviously, you can't just think biceps onto your arms or dream you way to a double bodyweight squat. And yet.... sometimes it seems that when I think of squats, my quads respond. When I am training with the mentality that "of course these rows will pack meat onto my back" it seems that the hypertrophy comes along faster than when I'm in the mentality of "well, I should probably do this."
How much do expectations affect your training outcome?
There was recently an article from NPR about how your perception of food can affect how your body responds to it. You can read it here.
The jist of it is, if you don't think that the food you're consuming is particularly filling or caloric, your levels of ghrelin (a hunger promoting compound) doesn't subside as much as if you think you're eating SO MUCH FOOD. Even if the actual caloric content stays the same.
If that works so well for eating, why not for training.
So really, this is just a thought experiment, but...
I'm willing to bet that if two people busts their asses, and one person thinks "I'm awesome, strong, and just going to get stronger!" while the other person thinks, "Gee, I hope that was enough work. What if I don't make the gains I want?" you're going to see some different changes in the biochemistry of each person.
It could be anything from that mentality makes me choose heavier weights or higher reps or it could actually change the way my body responds at a biochemical level. Either way, that would be a pretty cool study to do if someone could figure out how to do it. Humans are so fickle, after all.