For me, it starts with having confidence that I can meet the challenge. Then I get habituated to meeting the challenge, where the concept of quitting doesn’t really factor into my thinking.
The thing that really landed this for me when I started mountain biking is I signed up for the Leadville Silver Rush 50 mile, 7k feet of climbing, race. The longest MTB ride I had ever done prior was 30 miles, in flat land Illinois. Going into the race, I didn’t know if I was going to be able to finish.
From then on, my expectations were reset - I knew I’d be able to complete rides of that distance and duration. Then I went on to ride the LT100, Unbound 200, some big multi day bike packing trips… so I now have confidence I’ll be able to finish rides like that, and I don’t really think about the possibility of not finishing.
It’s similar in training - assuming - and this is important - that the workout intensities are set appropriately (ie not off an inflated FTP), and that you’re not burning yourself out by doing too many intense sessions.
The problem with indoor TR-style power-based training, though, is the goal can become to complete ever more difficult workouts… in which case you’re going to start failing workouts, which can lead to a risk of becoming habituated to quitting.
I’d recommend instead (or in addition) you find some challenging outside rides to tackle, and use those to build confidence and get habituated to not quitting. Eg - go ride a 100 mile loop. It’s hard to quit when you are halfway through!
This video may seem a little cheesy from the outside, but it’s genuine. Worth a watch/listen.
Same here re: counting with eyes closed. I started doing it while I was rowing. Because the breathing of rowing must be sync-d with the stroke-rate, it can be very difficult to get enough oxygen without good timing/technique. When I was a new-ish to rowing I was very much struggling to breath properly, and I kept blowing-up and failing at intensities that I thought I should be able to hold onto. While there may have been nothing I could have done without better breathing technique, I often wondered afterward why I didn’t just push on for longer. Eventually I improved, and got to the status of trying to improve my will-power. One successful example was during a 30min TT for distance (which I’m still very proud of the result): I got 20min in and was thinking “uh-oh… I may have overcooked this”. It was pretty much all eyes-closed counting after that. I’d count 10 strokes at a time, and associate it to a different finger on each hand (right thumb, right index, right middle, …, left ring, left pinky). That got me 100 strokes per round, and I’d repeat it. In the last couple minutes where my O2 saturation was probably dropping, I shortened to 5 strokes at a time.
For cycling indoors where I don’t need to pay attention (eyes closed), I’ll do the same thing, except I’ll count 10 pedal strokes at at time, though I’ve now started adding each foot (getting me 120 total pedal cycles per counting round). If I’m standing, this will probably be around 1:40-1:45 in duration, and if I’m seated this is probably around 1:15 in duration. I find I’m able to keep going if I stop watching the time and just pay attention to my body, breathing, and counting. I’ve semi-consistently seen my HR increase shortly after I look at elapsed-time or time-remaining, so now I try not to watch the clock when I’m really suffering.