I have been doing strength training regularly for a few years and I can clearly see the benefits now. However, I am wondering what if I stop? If I completely stop strength training for one year, or five years, or ten years, will my earlier experience of strength training still benefit me in any sense? In other words, after stopping exercising for quite a while, is there any significant difference between my body and one who has never done any strength training?
I'll attack this from two angles. The potential and the actual.
This is the more obvious. A major benefit of being previously trained is becoming trained again is much easier. In other words, "muscle memory."
Ideally, you will start exercising again at some point. You will gain muscle more easily than if you never trained.
Furthermore, you will have some coordination that kicks back in / never left. In other words, "like riding a bike."
I've trained former college athletes, in their 50s and it was obvious they had an athletic background. They picked everything up much quicker than Jane Doe who had never worked out before.
(I think this more what you're asking.)
You can find inordinate amounts of evidence that former athletes i.e. former very active people, live longer than people without that background.
Granted, knowing exactly how long they can be sedentary after say being a pro athlete, how much of the benefit is genetic vs from the activity, how much activity they maintain after playing, etc. I don't believe that's been really figured out anywhere. (And may never be, considering if you want to do that properly, you're talking a very expensive study.)
For example, athletes are often found to have higher socioeconomic status after playing. Is the benefit from the activity, or having more money? Many athletes have a larger, and closer, group of friends from their playing days. Social support is a huge factor in quality of life. (Some of these factors you could control for; others it's much harder to.)
But it's not unreasonable to say something like becoming more physically coordinated tends to stick around, and when you're older and falling becomes increasingly likely to significantly impair your life, that previous coordination could make you less likely to fall.
Or that something like heart disease is cumulative. Thus, if a person from 20-30 years old doesn't accumulate as much of it as a sedentary person, because they were active in their 20s, then 50 years later -all else being equal- they still have less of it than the person who has been sedentary the entire time.
Furthermore, being formerly active has mental benefits such as knowing certain things about nutrition, unconsciously taking the stairs rather than the elevator, possibly being at a healthier weight because you're more aware of the negative effects of obesity than someone who never got into fitness, never smoking, and so on.
Of course, if you stop working out and go to an extreme, then it's not going to matter much. I had one client who never stopped talking about his military days and how much he could run, yet was currently a diabetic and 350 lbs. That running wasn't too relevant anymore! Or NFL lineman. They're found to have higher risks of heart disease. Their playing environment -needing to be so big- wasn't helpful.
But on average, yes, your body is different after it's become trained.
Here's one study you might be interested in, which quotes another study saying former athletes did not appear to be more active than non athletes after playing, suggesting any benefits were from the past, not from e.g. continuing to be more active.
- Do Elite Athletes Live Longer? A Systematic Review of Mortality and Longevity in Elite Athletes (See the Holistic Health section.)