There is an article that stated she was hesitant to do it nude because of her weight. Hard to believe it but she is 160 pounds but it's mostly muscle. Hussien Bolt is like 190 which you'd think is about 30-40 pounds too heavy for a runner but muscle mass weighs more than fat which is why both weigh heavier than they look.
I think you misread that article. She was hesitant to pose because she thought it sent the wrong message to kids about being super skinny. She agreed to do it if they did a "tasteful" pose and stated her weight. Maybe they positioned the arm like that for a reason?