The Norwegian 4×4 workout has been touted as the ultimate longevity-boosting workout, credited for significantly improving aerobic fitness scores over just eight weeks.

Popular among runners and developed by researchers from the Norwegian University of Science and Technology (NTNU), it involves performing four sets of four-minute cardio intervals at 85-95% of your maximum heart rate, followed by three minutes of light recovery.

The 2-2-2 workout is more than an internet trend. It’s a full-body, time-saving, and strength training workout that can be done in the gym or with dumbbells at home, any time. It sounds too good to be true, but it’s backed by science and an expert PT.

Alain Gonzalez popularised the workout most recently, but the longevity perks for women are clear. Strength training offers women benefits, like reducing the risk of osteoporosis, sarcopenia, and cardiovascular disease. It also improves mobility and balance. However, we’re often the most time-stretched people in the gym, so anything we can do to shorten the time we need to spend there is appreciated, especially during the busy festive season.

In “The End of an Era,” Taylor Swift gives fans a behind-the-scenes look at the workout routine that helped her prepare for her “Eras Tour.”

Episode 3 of the six-part Disney+ docuseries follows Swift as she hits the gym throughout the tour, which ran for nearly two years.

Since each show lasted over three hours, Swift enlisted the help of personal trainer Kirk Myers to help her focus on endurance so she could maintain her energy throughout each concert.

“There are a lot of things that we pulled off on this tour that I’ve never even attempted on past tours. I think the longest show I ever did before was 2 hours and 15 minutes,” she said during the episode. “I never would have believed you if you would have told me we would be doing a 3.5 hour show. Now, saying that is one thing. Doing that physically is another.”

In order to dance and sing for that long, the 36-year-old had to make certain lifestyle changes.

“I really had to up my game in terms of physical training,” she said.

While reflecting on her workout routine, Swift joked that it wasn’t for the faint of heart. “I’ve never worked out this much in my life. It’s horrible,” she added.

Here are just a few of the exercises Swift focused on as part of her “Eras Tour” workout routine.

She Prioritized Strength Training

Episode 3 of the docuseries shows Swift in the gym prioritizing strength training. She can be seen doing the following moves:

• Battle waves and wave slams
• Ski machine
• Resistance band-assisted pull-ups
• Medicine ball sit-up throws
• Overhead hammer slam
• Assisted reverse crunch
• Hanging knee raise
• Medicine ball slams
• Medicine ball Russian twists
• Reformer plank pikes
• Crossover crunch with ankle weights
• Medicine ball side throws
• Bosu ball squat and press

She Did Lots of Pull-Ups But Hated Them

Swift can be seen doing pull-ups assisted by a resistance band and revealed that she has a “strong dislike” for them.

“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,” she quipped.

Swift’s personal trainer encouraged her and said she’s gotten “stronger” throughout the years while performing the exercise.

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

She Started Training 6 Months Before the Tour Began

While reflecting on her workout routine, Swift said she started planning for the tour early on.

“Six months ahead of my first rehearsal, (I was) running on the treadmill every single day at the tempo of the songs that I was playing while singing them out loud,” she said. “You just don’t want them to see you panting.”

Swift previously spoke about her intense treadmill workout in an interview with Time.

“Every day I would run on the treadmill, singing the entire set list out loud,” she told Time. “Fast for fast songs, and a jog or a fast walk for slow songs.”

She Did a LOT of Cardio

Dancing and singing for over three hours is a killer workout, especially when you’re running around the stage all night long. In the docuseries, Swift noted that two of her songs are particularly difficult to perform.

“‘1989’ and ‘Reputation’ are very high cardio. Anything’s hard when you’re scaling a stage that goes the entire length of an NFL stadium,” she said. “I think I run like 8 miles in the show.”