As a faller ; my prime was when I could hold my 394 with a 36" bar and chain, in my right hand by the grip and reach out and start a boring cut. On purpose. Without straining. . I used to Never loose hand shake's. Could hand over hand climb 25' up a 1" chocker with White Ox gloves on. I could load full 55 gal drums of gas or bar oil in the back of a 3/4 ton crummy just by rolling them onto my knee, picking them up and giving them a belly bump. At quitting time I could walk 1500' up out of a v notch none stop all week long after burning 2 1/2 gallons of gas thru an 064 or 288 . That was 20 years ago. However. I've injured most parts of my body quite a bit and I no longer live in the mountains. I always had strong muscles, but my tendons and ligaments were more fragile. Lots of back and hip injuries.
For climbing in my 20 s I could belt and spurs 80' one way in 30 seconds on boomstick size timber. Not anymore. I still outwork the 20 year olds easy and still keep a bushlin saw busy for 6-6.5 hours a day. But it really is hard getting out of bed in the morning. .
I would love to go back to bushlin. But I don't know if I could keep up. I'm pretty scared of the saying " This ain't a school for the young or a home for the old. "