I have often read the admonition “Check with your doctor before beginning and exercise program”. Here is a good link to a Mayo Clinic discussion on this subject: Mayo Clinic
I wholeheartedly agree with this advice. To which I will add my own advice - start slowly, and build as you can.
Which really is not the subject of this posting. As I gradually became more fit I regularly found myself comfortably on a plateau - not really advancing in my strength or fitness, but not bad either. I can go back over the years and enumerate the specific events that broke me out of these routines and got me back on a growth curve. One in particular comes to mind - I had watched a very fit, very strong young man for several weeks doing some pretty heavy lifting. And he had noticed that I did a lot of body-weight-based exercises - push-ups, chin-ups and the like. One day we got talking and I asked him to show me his leg routine. He did the next day. The day after that I could not walk up stairs. Or bend over. But, he showed me that I was in fact strong enough to do much more - I just went a little far with that first step.
Reminds me also of a young man who one day asked if he could work out with me - interestingly, also a leg work-out. He was pretty strong, and did some good exercises, some hard exercises. Then I didn’t see him for a week. He was so sore the day after our workout that his wife made him promise not to work out with the crazy man ever again.
While I wish I had a magic formula to offer, I don’t. I know that I am stronger now then I was last year, and, was stronger last year than the year before that. In fact, each of the 3 years that I have been retired have seen significant increases in my strength and endurance. And have seen specific episodic periods when I over did it as I took on a new routine or took an existing routine to a new level.
In fact, Monday of this week was just such a time - the first day that I worked out with Olympic exercise rings - or gymnasts rings. Let’s just say that Tuesday justified a light workout, and today was still not up to full speed. But, and I have to stress this, I can tell that rings will move me up to a new level that is unbelievably higher than where I am now.
One resource that I can recommend is the book “Younger Next Year”. It will help you begin to understand the physiological rational behind pushing your body with rigorous exercise routines. And it will tell you more about my goal - which is to be absolutely more fit, stronger, and yes, younger next year.
The bottom line of this posting is that you will have to over do it once in a while to keep improving. With time you will get a lot better at knowing your body, and its limits. You will learn which muscles you can readily strain badly enough that they will hassle you for weeks. And you will come to relish the soreness that tells you that you are transcending a plateau. Start slow, learn your body, both its strengths, and weaknesses, and then do everything you can to grow, and become truly younger next year.