It would not be wrong to say that the direction of bodybuilding competition changed because of a butt. Or to be more precise, the gluteus maximus muscle, which comprises the largest part of what is idiomatically called "the ass." The gluteus maximus is the bulkiest muscle in the human body, although the degree of that bulk varies with individuals. Some people complain of having "no ass," usually a reference to a flat-appearing gluteus. This is of concern, whether openly stated or not because the glutes (as they are often called) are without a doubt a sex symbol. Indeed, some scientists speculate that women wear high cleavage dresses because the partial exposure of their breasts in such dresses mimics the appearance of the human buttocks or glutes, thereby sending a silent, but potent sexual signal that signals femininity comparable to having a neon light on their chests. This is thought to have evolved from animal behavior. Many species of female animals signal their readiness for procreation by presenting their buttocks to males. In some cases, these rear ends even turn red to further signal that they are prepared to accept the male animal's sexual advances. Indeed, unless the male animal gets such signals he will not make any attempt to mate with a female. Too bad such signals could not be sent by humans; it would save a lot of frustration and rejection!
In terms of bodybuilding, the glutes have elicited both favorable and unfavorable responses. The appearance of "ripped" glutes marked by actual muscle striations first appeared in a bodybuilding competition in the 1980s and set a new standard for muscularity marked by ultra-low levels of body fat. Showing striations in the glutes was a distinct sign of low body fat since the glutes tend to accumulate fat, especially in women. This woman is Kim Kardashian, who appears to have no talent other than having an extremely large butt. Why there is such a fascination with her behind is beyond my comprehension. She clearly is a textbook example of steatopygia. How much muscle is included with her obvious large fat accumulation in the butt is anyone's guess, but I suspect that it's 90% fat and 10% muscle.
For those who are interested in developing muscular glutes, in contrast to what Kardashian has, there is a multitude of simple weight exercises that exercise these muscles effectively. As noted, you can use machines that directly target the glutes, such as the Butt Blaster type machines. Or you can work them just using common thigh exercises that involve the glutes, such as squats, leg press, lunges, and other exercises that don't require much skill. If you want to emphasize the glutes when doing squats, the lower the squat position, the more that the glutes are involved in the exercise. With leg presses, placing your feet lower on the platform and also doing a full movement will . . .