D

The burn in Mingi’s core was no longer a stinging enemy; it had become a familiar, almost comforting hum. He adjusted his grip on the leather straps of the Reformer, his knuckles white as he prepared for the next set of resisted leg circles.

"Focus on the pelvis, Mingi-ya," his instructor, a petite woman with the strength of a titan, called out from across the studio. "Don't let your lower back arch. Keep that stability. You’re working the deep stabilizers today."

Mingi grunted, a low sound caught in the back of his throat. He’d started these private sessions three months ago on a whim, mostly because Hongjoong had mentioned his posture was starting to slump from long hours hunched over a MIDI keyboard. He’d expected some light stretching and maybe some improved flexibility for their more demanding choreographies. He hadn't expected to feel like his entire center of gravity was shifting.

As he moved his legs through the heavy resistance of the springs, he could feel the fabric of his workout leggings straining. It was a sensation he was becoming increasingly wary of.

When the session finally ended, Mingi sat up, wiping sweat from his forehead with the back of his hand. He felt taller, more aligned, but there was a distinct heaviness to his lower half that hadn't been there in the spring.

In the locker room, he pulled off his damp shirt and caught his reflection in the full-length mirror. He froze.

He had always been tall and lanky—the "pencil" of Ateez, as some fans jokingly called him in the early days. But the man in the mirror was changing. His waist, which had always been narrow, had tucked in even further, carved out by the relentless oblique work and deep core engagement. It made his shoulders look broader, sure, but it did something else entirely to his hips.

Mingi turned to the side, craning his neck.

"No way," he whispered to the empty room.

His thighs didn't just look toned; they looked dense. The muscle had filled out in a way that made his favorite vintage denim feel like a death trap lately. And his backside—Mingi poked at his hip—was undeniably firmer, more prominent. The pilates hadn't just fixed his posture; it had rebuilt his foundation.

He pulled on his oversized hoodie and a pair of baggy cargo pants, hoping the extra fabric would hide the sudden structural shift. He wasn't ready for the members to start making comments.

***

The practice room at the KQ building was stiflingly hot by the time Mingi arrived. The rest of Ateez were already there, stretching or marking through the bridge of their latest title track.

"You're late," Seonghwa noted, though his voice was kind. He was currently folded in half, his forehead touching his knees. "Pilates again?"

"Yeah," Mingi said, dropping his bag in the corner. "Traffic was a mess."

"You've been going a lot lately," San said, popping up from a lunging position. He scanned Mingi from head to toe with that predatory, observant gaze he usually reserved for stage performances. "It’s working. You’re standing differently. Very... upright."

Mingi laughed nervously, rubbing the back of his neck. "Just trying not to have the back of an eighty-year-old man, San-ah."

"Let's get to work," Hongjoong called out, clapping his hands to gather their attention. "Positions for the second chorus. From the floor transition. Let's go!"

Mingi took his spot. Usually, the floor work was the part he dreaded most. Being the tallest meant he had more limb to manage, more weight to shift quickly. But as the music flared to life—the heavy bass of the track thumping through the floorboards—he felt a strange new power.

When he dropped into the deep squat required for the transition, his legs didn't tremble. His core held him like a vice. He felt grounded, explosive.

However, halfway through the high-energy sequence, he felt a familiar, dreaded tug.

*Rip.*

It was faint, muffled by the music, but Mingi felt it in his soul. He stopped moving abruptly, his hands flying to the back of his thighs.

"Mingi? Why'd you stop?" Wooyoung asked, tilting his head. "You were actually on beat for once."

"I... uh..." Mingi felt the blood rushing to his ears.

"Did you hurt yourself?" Yunho walked over, concern etched into his features. He reached out to pat Mingi’s shoulder, but Mingi flinched away, backing toward the wall.

"I'm fine! I just... I think I left my water bottle in the car. I'll be right back!"

"Mingi, you're holding your water bottle," Yeosang pointed out dryly, gesturing to the plastic jug sitting three feet away from the rapper.

Mingi looked at the bottle, then at his members. He felt the cool air of the practice room hitting a spot on the back of his thigh that should definitely have been covered by fabric. The seam of his workout pants had surrendered to the sheer volume of his quads.

"Is your leg okay?" Jongho asked, squinting. "Your pants look... tight."

"They're not tight," Mingi squeaked, his voice jumping an octave. "They're just... aerodynamic."

"Mingi-ya," Hongjoong said, walking over with a suspicious smirk. "Turn around."

"No."

"Mingi."

"I'm shy today, Hyung. Let's just keep dancing. I'll face the mirror the whole time."

Wooyoung, never one to let a moment of vulnerability pass without exploitation, darted behind Mingi before the taller man could react. He gasped, a sound so loud it echoed off the mirrors.

"Oh my god," Wooyoung breathed, his eyes wide. "Mingi! What have you been eating?"

"Nothing! I’ve been doing pilates!" Mingi wailed, finally dropping his hands in defeat.

The members crowded around, and Mingi wanted the floor to open up and swallow him whole. There, along the inner seam of his right thigh, the stitching had pulled apart, revealing a glimpse of pale skin and the sheer density of the muscle beneath.

"It's not just the rip," San said, leaning in with a look of genuine scientific interest. "Mingi, your waist is like... this small." He held his hands out to mimic a tiny circle. "But your legs... you’re built like a speed skater now."

"I told you the reformer was dangerous," Yunho teased, poking Mingi’s hip. "You’ve got a shelf back there now, Min-ah. You could set a coffee cup on it."

Mingi groaned, covering his face with his hands. "I didn't mean for this to happen. I just wanted to fix my posture! I didn't know my body would take it as a challenge to grow in only one specific direction."

"It's the core strength," Seonghwa said, ever the voice of reason, though he was biting back a smile. "You're engaging your glutes and your thighs more in everything you do. Even when you’re just walking. It’s passive hypertrophy."

"I don't care what kind of trophy it is," Mingi muffled into his palms. "I can't fit into my stage pants for the comeback. I tried them on this morning and I couldn't get them past my knees. I thought the laundry shrunk them!"

Hongjoong sighed, though he looked more amused than frustrated. "I'll have to talk to the stylists. We’re going to need to adjust your measurements. Again."

"The fans are going to lose their minds," Wooyoung cackled, circling Mingi like a shark. "Do you realize what’s going to happen when you do the hip thrusts in the second verse? You’re going to cause a national emergency."

Mingi peeked through his fingers. "You think it’s that noticeable?"

In response, Yeosang walked over, picked up a tablet, and snapped a quick photo of Mingi’s profile before the rapper could protest. He turned the screen around.

Mingi stared. In the baggy clothes, he looked sturdy, but the way the fabric draped over his lower half was undeniably different. The silhouette was curvy—there was no other word for it. His waist dipped in sharply, and his thighs and backside flared out in a powerful, muscular arc.

"I look like a Pixar mom," Mingi whispered in horror.

The room erupted into chaos. Wooyoung fell to the floor clutching his stomach, his high-pitched laugh piercing the air. Even Jongho was leaning against the barre, shaking with silent laughter.

"A Pixar mom!" Wooyoung shrieked. "I'm calling the stylists right now. We need to get you a floral apron for the next music video!"

"It's a good look!" San insisted, trying to be supportive while still grinning. "It shows you're healthy. And strong. Honestly, the choreo is going to look so much more grounded now."

"I have to buy all new pants," Mingi lamented, looking down at the ruined seam of his leggings. "Every single pair of jeans I own is now a hazard to public decency."

"Look on the bright side," Yunho said, draping an arm around Mingi’s shoulders. "At least you don't have to worry about falling over during the one-legged turns anymore. You've got enough of a base now to survive a hurricane."

Mingi sighed, finally letting his hands drop. He looked at himself in the mirror again. It was a change, certainly. He felt heavier, more substantial. When he moved, he felt a sense of control he’d never possessed during their debut days.

"Fine," Mingi said, a small, shy smile finally breaking through his embarrassment. "But if the stylists give me leggings for the stage, I'm blaming all of you."

"Oh, they're definitely giving you leggings," Hongjoong called out, already typing on his phone. "I just sent the 'Pixar mom' comment to the performance team. They’re suggesting we move you to the center for the dance break."

Mingi’s eyes went wide. "Hyung! No!"

"Center Mingi!" Wooyoung chanted, hopping up and down. "The Power Thighs of Ateez! The Gluteus Maximus of Song Mingi!"

"I'm going home," Mingi announced, though he didn't move.

"You can't go home yet," San said, grabbing Mingi’s arm and pulling him back toward the center of the room. "We still have three hours of practice. And now that we know you have all that extra power in your legs, we're going to redo the jump sequence. I want to see some height, Mingi-ya!"

Mingi groaned, but as the music started up again, he felt the familiar pull of the rhythm. He stepped into the formation, his feet planting firmly on the ground. He felt the strength in his thighs, the stability in his narrowed waist.

He might have to replace his entire wardrobe, and he might never live down the nicknames from Wooyoung, but as he launched himself into the air for the first jump of the chorus, he felt like he could fly.

He landed with a solid, silent thud, perfectly in control.

"Nice!" Hongjoong yelled over the music.

Mingi caught his reflection in the mirror—the sharp line of his jaw, the breadth of his shoulders, and the new, powerful curve of his legs. He smirked. Maybe the pilates wasn't such a bad idea after all.

He just needed to find a tailor who worked with heavy-duty denim.

As the practice continued, the members kept stealing glances, their teasing turning into genuine awe as they watched Mingi move with a newfound grace and power. He was no longer just the tall, lanky rapper. He was something more imposing, something more grounded.

And if he caught Wooyoung trying to take a video of his "new profile" during the break, Mingi just used his newfound leg strength to chase the younger boy across the room, cornering him with an agility that left everyone breathless.

"Okay, okay! I give up!" Wooyoung yelled, trapped between the wall and a very muscular Mingi. "The pilates is good! You're a beast! Just don't sit on me, I’ll be crushed!"

Mingi laughed, the sound deep and vibrant. He felt good. He felt strong.

And as he walked back to his bag to grab his water, he made a mental note to book an extra session for next Tuesday. If he was going to be the "Pixar mom" of the group, he was going to be the strongest one anyone had ever seen.