Taylor Swift reveals ‘horrible’ workout she used to prepare for 3.5-hour Eras tour — and the move that inspires ‘rage and resentment’

One look at the punishing fitness routine Taylor Swift endured to prep for the Eras Tour and it’s easy to see why she’d be ready to shake it off for good.

“I’ve never worked out this much in my life, it’s horrible,” the pop icon confessed in “The End of an Era,” the new six-part Disney+ docuseries that pulls back the curtain on her record-shattering tour.

But for Swift, 36, the sweat and strain were the price of delivering a blockbuster show that drew 10 million fans around the globe.

“There are a lot of things we pulled off on this tour I never even attempted on with other tours,” Swift said.

Before launching the nearly two-year trek across five continents, the longest set that the Grammy winner had ever attempted clocked in at two hours and 15 minutes.

“I never would’ve believed you if you told me we were doing a three and a half hour show,” Swift said. “Saying it is one thing, doing it is another.”

To pull it off, the “Opalite” singer said she had to seriously level up her physical training.

“Six months ahead of my first rehearsal, [I was] running on the treadmill every day to the tempo of the songs I was playing while singing them out loud,” Swift said. “You don’t want them to see you panting.”

For faster tracks, she ran; for slower songs, she eased into a brisk walk or jog, she previously told TIME in her 2023 Person of the Year profile.

And there was plenty of ground to cover.

The Eras Tour doubled as a musical time capsule, celebrating each of Swift’s studio albums as its own distinct “era,” with every show pulling songs from multiple records.

“1989 and reputation is high cardio,” Swift said in the docuseries — though she added, “Everything is hard when you’re scaling a stage that goes through the entire lengths of an NFL stadium.”

All told, Swift estimates she runs about eight miles over the course of each show, which spanned more than 40 songs.

While she handled her cardio regimen on her own, Swift leaned on longtime trainer Kirk Myers for strength and conditioning.

“Taylor is the most resilient person I have ever met,” Myers told Us Weekly last year. “It’s super-inspiring to see her consistently overcome obstacles and become better and stronger in the end.”

Fans get a behind-the-scenes look in episode three, which shows Swift breaking a sweat inside Myers’ gym.

The pop star tackles battle ropes, a comprehensive exercise that’s good for cardio, endurance and upper body and core strength.

She also did assisted pull-ups — an exercise she made clear she does not enjoy.

“In no way do I ever apply this … at any point in the show, I just want to flag that as I do every time I have to do pull ups,” Swift said. “Strong dislike. Two thumbs down.”

But Myers pushed back. “You have gotten stronger on those throughout the years,” he told her.

“It’s from all the pent up rage and resentment I have for them,” Swift quipped.

The “Cruel Summer” singer is also shown powering through leg raises, weighted side twists, crunches, knee-to-elbow moves and sledgehammer workouts — all aimed at building the stamina she needed for her marathon performances.

“I give her a difficult exercise or challenging workout, not only is she able to complete and push through it — but she also perseveres,” Myers said. “This ultimately makes her stronger, better, and faster.”

And before stepping onstage, Swift put in just as much time at the dance studio with choreographer Mandy Moore.

“I had three months of dance training because I wanted to get it in my bones,” Swift told TIME. “I wanted to be so over-rehearsed that I could be silly with the fans, and not lose my train of thought.”