Being out-of-shape and overweight is a risk factor for … shoulder pain? Indeed it is — see Rechardt et al. And that’s probably not because the shoulder is a weight-bearing joint (unless you do far too many push-ups). The problem is probably that biochemistry can make the tissues of the shoulder more vulnerable to various kinds of injury. In other words, it’s not about anatomy getting pinched or overused, per se… it’s about those tissues being so fragile and prone to inflammation that it takes very little stress to cause trouble.
Okay, this guy bears weight on his shoulders. And a bit too much of it. But for humans, obesity threatens the shoulders with chemistry, not load.
This is one good example of how biology, systemic vulnerability, and lifestyle medicine are probably more important in musculoskeletal and sports medicine than they have been given credit for. I think that it’s the main reason structuralism — the excessive focus on “mechanical” factors like asymmetry — has proved to be such a big nothing burger over the last few decades. See: