As a 71 y/o thru-hiker I check off most of the boxes for using trekking poles that Ryan mentioned. I also couldn’t do it without the poles. They have saved me from going down so many times I’ve lost count, but certainly hundreds of times in the 10K miles I’ve hiked in the last seven years.
Ryan did not mention it, but along with the studies on the feet, I wonder if there is any data on the ankles and knees. As a biped, my ankle, knee and to some degree hip muscles are constantly compensating for uneven terrain. With poles I am a quasi-quadraped and I feel that my ankles, knees, and hips get to rest a little more and are less sore at the end of a 20 mile day than without them.
Anyway, I’m a big fan of poles.