Get a kettlebell or two (different weights) and do swings, lots of them. This worked for me.
They can be done any time, indoors or out. It's much more minimalist than a squat rack so I think its a lot easier for most people to start (unless you're already going to a gym frequently or have your own bar).
If you can do ~100 daily with ease, consider a bigger weight.
In my own experience, the three best things for reducing lower back pain were losing weight, squats, and crunches. The weight (~300 lbs to ~240 lbs) of course was the biggest thing to get me from "rarely I can't even stand up from bed easily" to "rarely do I ever get lower back pain".
This is good advice, thanks. I used to get crippling back pain once a year (a cramp that would render me unable to walk for a week) and nothing for the rest of the year.
Now I get low pain all the time, but it's more of the "sore muscle" variety. It does make me walk a bit oddly, at least until I walk it off, but I wish I didn't get that either.
The difference between the two was that i gained weight but started Pilates. I'm losing weight now but I'll start doing squats and crunches as well, thank you.
For me it was squat and deadlift with a lot of stretching.
Though for me a lot of the lower back pain came from really tight hamstrings so the stretching was important for that (and you can't really do squats and deadlifts with proper form without enough flexibility)
McGill works with famous weightlifters and athletes which gives him some bro-science cred, he has actual science-science cred but he's also very good on what's actually important for the average aging person.
Squats and deadlifts are considered the best of all excercises, and will give you a strong, healthy back. Focus in form, not weight, and if you have existing issues find a variation that works for your body (trap bar, Smith machine, different grips and feet placements).
There are a lot out there but take it easy at first. I started trying to do leg lifts and planks while my back was still hurting, and it only made it a lot worse. Stretching and walking until the pain subsided and then strengthening very slowly is what has worked for me.
