The survivor shows like Survivorman and Man V Wild seem to reinforce that it's the mental side of survival (including preparedness) that will be the best predictor of success/failure in outcome, much moreso than physique. Yeah, since they know that they are heading into a rough situation, they definitely do store up some energy via body fat. Food is always one of their scarcest resources to obtain. Yes, they can climb and hike like billy goats as part of their technical training. But, like people said in the thread, one never knows when a critical situation might arise. Those that can remain calm, stay positive and establish a plan seem to be the ones with the best odds of making it out the other side.