I think of strength training as a form of retirement saving. Just as we want to retire with enough money saved up to sustain us for the rest of our lives, we want to reach older age with enough of a “reserve” of muscle (and bone density) to protect us from injury and allow us to continue to pursue the activities that we enjoy.
It is much better to save and invest and plan ahead, letting your wealth build gradually over decades, than to scramble to try to scrape together an individual retirement account in your late 50s and hope and pray that the stock market gods help you out. Like investing, strength training is also cumulative, its benefits compounding. The more of a reserve you build up, early on, the better off you will be over the long term.
Yet unlike some guys in the gym, I’m less concerned with how big my biceps are or how much I can bench press. Those might matter if you’re a bodybuilder or a powerlifter, but I’d argue they matter less in the Centenarian Decathlon (or in real life). A far more important measure of strength, I’ve concluded, is how much heavy stuff you can carry. I say this on the basis of my intuition but also research into hunter-gatherers and human evolution. Carrying is our superpower as a species. It’s one reason we have thumbs, as well as long legs (and arms). No other animal is capable of carrying large objects from one place to another with any efficiency. (And the ones that can, like horses and other livestock, do so only because we bred and trained and harnessed them.)