My new, harder, weights routine
The machines I use at the gym allow me to push or pull to lift a weight which then falls back under gravity.

Until recently I would push and relax, push and relax.
For the last few weeks though I've reduced all my weights a bit and am doing something much harder:
- push (explosively, for power)
- hold for a few moments
- ease the weight back down slowly and under control
This hold and slow release is actually quite hard and tiring.
I'm more of a slow and steady 'tortoise' so the 'explosive' first movement is something I'm still working quite hard on.
Various YouTubers I follow have pointed out that learning to balance on one leg is all very well, but if you start to fall, for example, you need a quick movement to save yourself. I'm applying that notion to all the movements I do. It's a matter of developing power rather than just strength.
Side note: decades ago I was a school teacher. One 13 year old boy went to boxing classes I think. He would wait until I was looking elsewhere, but so he was still in my peripheral vision, then he'd flash his arm up into the air and down again so quickly that by the time I turned my head there was no hand up asking for attention. 🤣
Re 'power' — Effectiveness of power training compared to strength training in older adults: a systematic review and meta-analysis says:
Power training offers more potential for improving muscle power and performance on activity tests in older adults compared to strength training.
If something unexpected comes along I want to be able to move quickly to deal with it.
As for the 'hold' and slow release instead of allowing gravity just to return the weight: that's actually quite demanding too and I feel they're both building strength.
After a couple of years at the gym doing up / down weights I'm enjoying this new routine.