I don't know if this post is the sort of thing you can agree or disagree with, but I think it's been an actively harmful mental model for guiding my training, which is why I no longer think in those terms.
Excellent point psmith. I too have struggled mightily with pushing my body into the "suck" and thus reaped the rewards "injuries" too often to count.
The mental toughness training I am talking about though is not done for "chest beating" but a specific purpose to prepare one's mind for potential life threatening situations and good decision making ability therein.
In my experience it has been advantageous to train mental toughness and mountaineers/combat arms folks will specifically understand what I am talking about. When I was in the infantry, they intentionally caused numerous types of discomfort (mental and physical) to increase your survivability and adaptability in difficult circumstances. It was something that was specifically trained, because one day you would have to make decisions under very stressful circumstances that could cost your life, or worse, your Soldier's lives.
Earlier offwidth mentioned that an experienced mountaineer asked why would he train mental toughness when he is going to suck on the mountain anyway? IMHO, the reason is you need to know how your body is going to respond in such situations before it may cost you your life.
A lot of what I do has been with one of my 5 kids in tow, and we have had "adventures" where if something went wrong we were simply going to die. I say that not to be dramatic, but it just is. Even with modern satellite communications there are many locales on this earth that rescue is not quick enough, or they simply cannot fly very often due to consistently poor weather. Knowing how my body works when wet, tired, cold and hungry has helped me personally many times. Yes, the actual experience of doing such things has been the best mental toughness teacher, but I believe there are some things that we can do to prepare ourselves, somewhat, prior to those things happening.
Some mental toughness training is skill learning. This is just a small example. As much as I take my kids out, one skill I taught them (3 of 5) early on was how to make a fire with COLD hands as one day it could save their lives. When I mean cold, I mean cold to the point where you can barely close your index finger to your thumb. In the safety of our back yard I intentionally got there hands cold to the point of extreme discomfort (not injury) and then instructed them on how to start a fire in such a state with a magnesium striker. Cocoa and warmth awaited them in the house, but that activity boosted their confidence tremendously and I have comfort of knowing that if ever in that situation they already know what to do and will not panic.
To train the physical part of mental toughness I have found that one has to choose activities that require nearly 0 skill, thus when the body is fatigued there is very low risk of injury. Here are my top three:
1. Rucking (medium ruck (<=50lbs))
2. Farmer's Carries
3. Crawling (unloaded)
The British SAS and USA Delta Force utilize rucking as one of their primary selection processes.
There is little chance of injury to throw on a ruck and walk until you think you cant walk anymore, then walk some more. At the end sometimes throw in life saving skill practice.
Anyway, I am enjoying the discussion and everyone's thoughts on this topic. Happy Monday!