There have been over a hundred girl groups who've made their debuts, but only 20 or so are in the public light. What does it take for a talented group to really shine in a pool full of equally talented rivals? The answer is practice, practice, and more practice. Even for the more seasoned girl groups like Nine Muses, comeback training is as hectic and uncertain as their debut process. Sports Chosun received access to their rehearsal rooms to get a sense of what it's like for a girl group to pass their screening test for a comeback. Reporters were surprised to find that getting tested was a process that stretched beyond their debut -- t's common for a group to get everything evaluated, from their skills to their concept, choreography, and stage outfits. Should there be anything that doesn't meet standards, their entire comeback could be pushed to the backburner. The girls had been ordered, "If you don't pass the final test, there will be no comeback." Nine Muses' member�Hyuna expressed, "We have to be perfect in front of the public. I get so mad at myself whenever I make a mistake. The 'final test' is where we get our skills evaluated before we're put out to the public. There's a lot of pressure because our comeback is on the line." Over 20 staff members ranging from managers to stylists are present for the 'final test.' Everyone has a hardened look on their faces, most likely because it's not only the girls who must suffer if a certain aspect of their comeback doesn't pass the test; their staff must trudge back to the drawing board, and restart the entire creative process. While the members go over their choreography, their stylists set up their stage outfits in the floor above them. A problem is discovered when the stylists notice that the comfort inserts they put into the girls' boots caused a difference in height. These boots were specially produced so that the members all stand at the same height on stage. The tallest wears 6 cm heels while the shortest member wears 9 cm. After two hours, preparations finally end and the girls are ready to perform "News" for the very first time. Though the performance looked flawless, Star Empire staff didn't seem satisfied. After telling the girls to leave the room, the staff brought in their vocal, rap, and choreography teachers. "The choreography involving their legs is the point of the dance, but you can't really see that because of the fabric in their outfits," they criticized. After making amends on the spot with clothes pins, the girls came back for a second evaluation. They gave their all, but again, they failed to pass the test. The CEO explained, "There's no detail that's alive here. I want you to sing beautifully during the highlight, sing to the point where I can see the veins in your necks." After two more stages (which brought the girls to a point of labored breathing at the end), the CEO finally gave his approval. The members said, "It was hard, but we're glad that we can make our comeback now. We can finally show you what we worked so hard to prepare." [gallery link="file" order="DESC"] Source + Photos: Sports Chosun via Naver