The next day after I discovered the exercise course, I went back to retry it.
I learned a lot.
First off, the thing I couldn’t do was a pull-up. Does aging prevent reading the directions? I can do a chin-up! Literally, one.
Second, hanging all my weight from my left arm is a non-starter on the horizontal ladder and also, anywhere anytime.
Third, like my left arm, the ability to balance got worse while it was unused. Of course, that happens at any age. (OTOH, mental tiredness really just began in my fifties.)
The next two days it rained. Today I plan to return to the course.