The artist is trying to depict a woman with extreme musucular definition everywhere other than their arms, who has roughly C to D sized breasts but nearly 0 body fat everywhere else, but the artist doesn't understand what musculature/skeletal structure around the waist/torso area actually looks like.
Its not impossible for an extreme female athelete/body builder to get that level of musucular definition ... but it would be quite difficult, the leg muscles are still probably unrealistically massive, the arms not matching the rest of the body would mean they basically never do upper body work, the breasts would likely be smaller if the rest of the body had such low body fat, and the way the muscles are drawn around the hip are just anatomically incorrect.
She's basically drawn as if she is a kind of human mutant that is missing about the lower third of her ribcage, and has a massive pelvis, and then has a fantasy musculature wrapped around that skeleton.