In emergency medical services (fire department stuff), ground level falls, like tripping in the yard, are treated very seriously until an assessment makes it reasonably clear that the particular fall is not serious. I remember from taking my EMT class being surprised at how serious this was viewed, what's the big deal, you fall, you just get up. While that is probably the case for younger people, older people who trip have a real risk of breaking something and depending on what gets broken, a ground level fall can be permanently life altering. This link says falling is one of the top three risks in retirement!
The processes that make people susceptible to a fall being a serious medical event are loss of muscle mass (sarcopenia) and loss of bone density (osteopenia). A simpler way to describe someone who has sarcopenia and osteopenia is that they are frail. Frailty often comes with older age, we've all seen people who look frail. The road to frailty starts early. We begin to naturally lose muscle mass around 30 and we begin to lose bone density around 50. The rate at which we individually become frail varies from person to person but someone as young as their 50's could certainly be relatively frail such that maybe they don't break bones all that easily but they get injured often and have trouble recovering and are unable to do things they would like to do or need to do.
I started cluing into this in my 30's when we moved to Walker full time. There were, and still are, a lot of older folks who remained very physically capable to what intuitively might seem like an old age. When I first joined the fire department there were quite a few in the group who were in their 60's, one even in their 70's, and were very capable, able to pass the pack test (annual fitness requirement for fighting a wildfire where you hike for three miles, wearing a 45 pound pack in 45 minutes or less). Today, we have several in their 60's who are able to do it.
The behavior modification needed to stave off frailty is quite simple; stay active and exercise. There are quite a few ways to get the job done, I think lifting weights which builds muscle mass and promotes bone density is the most effective and efficient way to avoid frailty but it is not the only way. Another important activity is trail hiking or as Nassim Taleb would say, walking on rocks. Walking on uneven surfaces, like a trail, results in improved balance which makes tripping less likely and when you do fall, there will probably be little to no consequence like if you were 40, healthy and happened to trip. Whether we become frail or not can be driven by our behaviors. This is great news. It is up to us individually to prevent/solve our own problems and while there are no absolutes, be able bodied to what might be considered an older age is possible. Here is a picture from a little over a year ago of a guy at my gym who was 78 back then, decline benchpressing 500 pounds. He is now 79 and can still do it. Not frail.
Also, it's never too late to start. Improvements can be made at any age but the sooner you start the better off you'll be.
All of this is of course a metaphor for effective retirement saving and planning. Our behaviors will likely have a huge impact on our outcome, we can start making improvements to our finances and planning at any age but the sooner we start, the better off we will be.