From what I know, at an older age, the chance of injury, not to mention the danger of injury, is way higher. The standard advice afaik is therefore to aim for lower weight / higher reps, because the risk of injury is therefore greatly reduced.
Not saying that 5x5 is necessarily incorrect, just that I would imagine a 8-10 rep based routine would be better for purposes of injury reduction (while still improving muscle conditioning, obviously).
Look at The Barbell Prescription book for more details - it’s about strength training after 40. Good form is important, and a trained coach can help with that.
Running is mostly a solitary sport. Lifting can be communal.
Slow and steady does it. If you hurt yourself by overdoing it when you are getting old, it will take much longer to recover.
This wasn't about optimal. If you ask me personally what I think optimal is, I think it's 5 sets of 5 with big weights, squats deads and bench. Mix in some other cardio activity 1-2 times a week, and you'll be a relative superhero.
But we're talking about people who have health problems and no history of exercise activity. For them, just starting to move is a huge step forward.
This lady probably wouldn't have reached 80 if she had continued on her current path. If we tell people like this, "you must lift weights", we will lost most of them. I have taught a few women to lift, even tiny ones, and of course they can learn and be very strong. But there's a serious stigma when it comes to weight lifting and women. They either think it's impossible, or they think they will end up looking like the woman in the article. Now I'm a fan of built women, but most women seem to really NOT want to look like that.