What I Learned From Lifting
The most important thing I learned from weightlifting is how many of my constraints are fundamentally in my head.
If you had asked me beforehand I would have said that "how much weight can you lift today?" is a physical fact you can nudge the tiniest bit up/down through willpower, but it's largely a story about the mechanical ability of your corporeal form.
Until one day I set up my rack to squat 240lb, and did a few reps thinking "damn that was harder than it should have been, I'm out of shape :(", and then realized I had counted wrong and squatted 270lb by accident.
I know for a fact that I could not have lifted it if my brain knew there was 270lb on the bar, and I don't mean that in a conscious psychological sense, I mean my brain would not have allowed my knees to bend if it had heard the number 270 when approaching the bar. But it turned out my body was perfectly able to lift that much.
I'm not sure exactly how this works, psycho-somatically: maybe your brain sets conservative limits on what it allows your body to do, maybe to protect you from injury? But it's wild to know know that my body is capable of vastly more than my mind will usually let it do.
(I have no evidence at all for this but I wonder if those stories about e.g. a parent lifting a car single-handedly to save their child is partly about this, their brain lets them use their full body power because of the emergency.)
I don't want to over-generalize from this insight, there are still plenty of things in the world that are not just brain-constraints, but having even one such vivid example of your brain vetoing something changed how I think about both brain-body connection and the self-imposedness of my limitations.
There's a smaller version of this that happens super regularly, which is: I don't feel like doing the last reps or sets of my workout, and sometimes I let myself just be lazy, and other times I buckle up and do it anyway.
And at some point all your progress in lifting comes down to how often you're able to make yourself do the slightly uncomfortable last reps/sets. It is very hard to do it, and it makes all the difference (even if you're 80/20ing the lifting in the first place -- there's a huge difference between 80/20ing and 50/10ing).
Lifting really highlights the classic tradeoff between doing things in groups and doing things alone: it's really hard to make yourself do the final difficult bit by yourself, whereas if you're around other people they can shame you into pushing through even when you don't want to. Working out (or simply working) with other people is inconvenient and expensive and annoying, but if they can make you do the hard bits that ultimately compound into your progress then it might be worth it.
Weightlifting has this unusual and lovely property that there's numbers and you record them and they go up.
This isn't true forever, you can reach a level where it's really really hard to progress, and there are bumps along the way even before that. But fundamentally, for a pretty long time, you can just keep showing up and doing the thing and watch your number get higher without any supernatural intervention.
And so few of the things I do have this clean linear relationship between effort and outcome that it gets hard to remember this. But weightlifting gives a much more visceral, grounded intuition to the philosophy that 90% is just showing up (consistently for a very long time).
When your progress plateaus, you need to find (and fix) your limiting factor. Weightlifting is full of surprising limiters, e.g. grip strength – I would never previously imagined that you could add 10% to a deadlift by improving your grip, but you can.
It's maybe less surprising than it first appears that it's these weird auxillary things that end up breaking your plateaus, because your training is focused on the Big Things to begin with, and overall that's where most of your progress comes from.
The plateau happens because you've got your Big Things to the point where they're no longer your limiting factors, and then you need to find smaller things to fix to make progress again.
It's much much easier to re-acquire muscle you had previously than to gain it for the first time. I'm not sure what to do with this information, except that I wish I'd started lifting much earlier in life, when mucle-gain is easier. Maybe it argues for doing some intense bootcamps (for various skills) a few times in life, so you can get to a skill ceiling that you will later find it easier to recapture? (Maybe you have to train for a couple of years and then do the intense bootcamp to really get the most out of this, I don't know).