I did not understand it.
Yeah, I have seen an 83-year-old put down a 40-year-old man like a rag doll.
I have seen my 72-year-old dad put down two drunk 30-odd-year-old guys (who were kicking an unconscious guy outside a bar).
But now, I at age 51, have no problem pulling a wine cork straight out after my pansy *** had to use those leverage winged cork screws a decade ago. Heck, in my teens and twenties I benched my weight (180-185 lbs.) but couldn't pull a damn cork straight out of a wine bottle!
Old man strength. I suddenly have it. I dunno what this phenomenom is. But there is something to it.