I think aside from good genes, which matter more than anything else, it's prolonged bad habits. Eating too much, or too little, too much alcohol, smoking, etc. By the time you're in your 60's, a lot of people have at least 40 years of abuse. I have found that limit strength, particularly in large muscles, doesn't suffer as much as endurance, recovery, small muscle control/strength and balance. As a strength competitor into my late 50's, I had occasion to keep track of stuff. At 65, I do notice deterioration. Graduated from HS at 127 pounds, with a 275 raw bench. Started competing again at 44. 137 pounds, 305 bench. 46, I was 148 pounds, 325 raw bench, 385 geared. 48, saw 165 pounds, 360 raw, 445 geared. 50, was where I made the most gains. 188 pounds, 425 raw, 700 geared. 55, 171 pounds, 355 raw, 520 geared. 58, 177 pounds, 340 raw, 530 geared. I didn't compete much raw, actually, and didn't work on it much. Pre Covid, (haven't worked out in a month) 65 years old, 176 pounds, 345 raw, 535 geared. Largely living on technique, now. I'm definitely not as strong as i used to be.
