A powerlifter who skews the BMI charts is different than someone who carries 50 pounds of fat.

The powerlifter is mobile and carrying the extra weight and has the strength to do so. The fat person is sedentary and doing whatever possible to NOT carry the fat. They do not have the strength to do so.

As someone that is about 30kg overweight, no my body can't carry that weight for a run. I used to run 5km 3 times a week. That was about 15kg ago. It was okay but now my knees just can't take that punishment. My shoes can't handle it either at well over 120kg they get destroyed after a few runs.

I would consider myself above average in strength after spending most of my 20s lifting regularly but that doesn't counter the impact of being this fat. It is shocking the impact it has on your life.

Your body builds the strength necessary to support your activity level. Unless you already have an active exercise regimen, an overweight person has generally only built the strength to support walking shorter distances. So the more overweight you are, the more careful you need to be when increasing distance while running.

Alternatives like cycling and swimming are better for the knees, especially for the old and overweight.

But powerlifters still have terrible conditioning and those who do it competitively will tell you that they're uncomfortably overweight for a lot of their daily activities.

for stress on the ligaments and joints weight is one the most important factors. Be it from a weighted vest, fat, or muscle. Joints of humans are not made to carry the weight of a strongman.