A guy I worked with when I was 16, he was maybe 17, we were both farmboys. I weighed about 135 and was loading 100lb bags of potatoes and carrying them up into a rail car and stacking them. He was about 200 lbs and strong, after some teasing, he picked up 3 100lb bags and loaded them in the rail car. One he carried in his teeth. None of us knew what a set of weights was.
Another farmboy bought a new Datsun 510 in 1970, he would lift the rear wheels a foot of the ground for fun.
No 100lb lifts happening now, without a jack.