From being in the military reserves for 7 years, and for 3 years being a full time instructor teaching on basic level courses. I've seen people break, 90% of the time they breakdown mentally. They shut down, unresponsive they hit a point were they just don't care anymore. I've seen this happen in 15 min workouts and I've seen it happen in 3-5 days field training with minimum sleep and shitty conditions.
Those that are able to mentally tough it out pull ahead, they continue to preform under demanding and unrealistic conditions.
I always enforce that the military is 90% mental and about 10% physical. You can be out of shape and still pull ahead if you have the mental capacity to continue on. Fitness makes the job easier but mental toughness is what separates people.
I take the same aspect to training people in the gym, and once again I've seen people reach that point were they "quit" before they even attempt to lift something. Women in general (based on my experience) will almost always defeat themselves before attempting a PR attempt. They get in the mind set that "its heavy" and before they even approach a bar they can't do it. Most men will do the same, but it takes a little longer for them to be effected.
Time after time though some skillful manipulation of weights and just flat out lying I've seen this over come. Nothing beats telling someone that the weight they thought was 10 pounds under their PR was really 10 pounds over. But it only works once, maybe twice, then clients start to get smarter.
When I lift I shut my mind off, I would like to say it was the military that created my ability to shut down and still function when required. But reality I had that ability joining at 17. I greatly relate this to my ability to achieve over a 500 pound deadlift and a 400 pound backsquat while doing CrossFit. The mental block of "I can't do it" is not there.
While this post is starting to get kind of long, really what I am asking is how does one train the mental side of fitness? How do you learn to shut the mind off, or not defeat yourself before you attempt something? I've been thinking about this for the last 3 weeks when my GF told me she wanted to achieve that zen state like I do when I lift and during workouts.
And to be frank, I honestly have no idea without putting her though the stuff I put troops though, and if I did that I'm fairly certain she would not love me that much anymore.