One can only apply x much force, as determined by our muscles ability to pull and our nervous systems ability to control that force when applied to situation y.
Think of it like a transistor. A pnp gate or similar. The device is rated for a maximum throughput of energy, of which the flow is controlled by another determinant (amount of energy into system). I think, the difference between our force mechanisms and a transistor is that we best apply control in recognisable patterns from feedback, and we can change how much control is required to leverage so much force. This is all relative to how you try and apply the force, and how much power you think you have, perceptually
I am sure you will see a pattern in my style of thinking, but if you can convince yourself you have a possibly infinite amount power relative to your ability to harness it, you will probably be able to kick out those extra few measures of energy, which may translate to those last 3 moves through the crux and into the victory lap. Its all about gurning, gritting the teeth and really putting the extra 99.99% of possible effort, on top of the 99.99% you are already using. This is when you can make your body do things that scare you. You surprise yourself, and can pull off those sequences that seemed impossible.
As I started up from the ledge at the pitch going up and right, I though nothing. I just had the move set I knew in my head. I had dogged through some of the harder sequence, but not move to move. The rope was in the first two bolts, so I was happy to have a go at the first hardish moves.
I started up though the first 3 clips of moves, and after a few grunts managed to hang the horrendous back-three sharp camming stacked pocket. Shocked that it held, I grimaced through the next little balance sequence, and then clipped the 4th bolt. moving left I hesitated with my feet 'how was I here'. I powered through to the split pocket, move feet, pull, 'I can't feel my left back-three', more hesitation, power out.
A standard scenario for most. If I hadn't hesitated, I probably would have made my first 7c route, on the first day of play, with little fuss. I will never be a Steve McClure. But I had really put all the beans in, chips down on the table, and made a solid effort. I pushed once again beyond what I though I was capable of. This had thrown me a little, but it is simply a case of learning to deal with it. Much like the fear. Finally today I had climbed beyond my level, above the bolts, and had accepted I was going to fall at some point or another. Much improved!
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From my experience I feel we need to learn to do hard moves well individually, and teach the nervous system how to apply maximal force in as many given scenarios as possible. Further more, we need to teach the un/conscious versions of ourselves, to push just that much harder, every time.
I still feel that bouldering is crucial to hard climbing, of any form. Be it on any medium.