Australian-based Pilates instructor and influencer Bailey Brown summed up the Pilates craze succinctly in a now-famous TikTok: "Gorgeous, gorgeous girls do Pilates. Pilates girls are hot."

Brown's post has gained the attention of millions, and the audio has been shared numerous times on TikTok.

The now-trending exercise has also become a favorite amongst celebrities like Duchess Meghan and Jennifer Aniston, and was popularized recently on the Met Gala red carpet by beauty entrepreneur Lori Harvey when she pointed to Pilates when Essence's beauty and style editor Blake Newby asked, "What's the trick to the abs?"

While most market research doesn't track Pilates separately from yoga, a report by Research Dive, the global Pilates and yoga studios market was expected to pull in revenue of $269.3 billion by 2028 compared to $127.7 billion in 2021 -- a compound annual growth rate of 10%.

Fitness influencers Elizabeth Endres and Dale Stabler of Sweats & The City told "Good Morning America" they were initially "intimidated" to try Pilates.

"However, when New York Pilates opened in their beautiful space in SoHo, it felt more approachable with class names like 'ABS ARMS A**'.'' We felt like they were trying to get the younger generation onto pilates and make it fun," said Stabler.

Endres added, "Pilates is a challenging, low-impact exercise that really works muscles and parts of your body in ways no other exercise can. It's about form and alignment and building a really strong foundation. We think a lot of people became tired of breaking their bodies down and wanted to explore all the benefits of Pilates. Not to mention, a lot of amazing studios have popped up in the last year or so."

What is Pilates?

Created by German physical trainer Joseph Pilates in the 1920s, Pilates is a low-impact exercise focused on form and alignment to enhance strength building as well as flexibility. It can be done on a mat or reformer and practiced through other Pilates apparatuses.

Club Pilates master trainer Shepherd Joseph told "GMA" that the most popular form of Pilates right now is performed on the reformer apparatus, which has springs that create multiple levels of resistance and straps for your arms and feet to move on a pulley system. "The reformer resembles a bed, as it was originally designed after a hospital bed when Joseph Pilates was rehabbing injured soldiers."

Joseph went on to break down different types of Pilates -- including everything from "classical" to "apparatus" formats.

Classical vs. Contemporary Pilates: Classical Pilates is a style that stays true to the original Pilates method, called Contrology, created by Joseph Pilates. Contemporary Pilates, seen at Club Pilates, is more of a blend of Joseph Pilates' original method and new-age research and exercises adapted from physical therapy.

Mat Pilates vs. Reformer Apparatus Pilates: Mat Pilates is a series of full-body exercises performed supine on a Pilates mat -- prone, kneeling or standing. Reformer Pilates uses the Mat Pilates principles and performs the exercises with resistance and the pulley system -- creating more intensity or assistance depending on the exercise.

What are the benefits of Pilates?

Pilates has a wide range of important health, fitness and overall wellness benefits.

Cedric X. Bryant, president and chief science officer of the American Council on Exercise, told "GMA" that it can also "improve muscular endurance, flexibility and posture, and in combination can lead to a reduced risk of injury as well as a decrease in existing chronic pain. And, because of the focus on mindfulness, Pilates can reduce stress levels, anxiety and depression."

He also added that Pilates can be an excellent option for people just starting an exercise routine, as well as those recovering from injury.

"It's great for at-home workouts and can be done in short bouts of around 10 minutes, so there is no need to perform a 60-minute workout to reap the benefits," Bryant said.

Additionally, several studies show that Pilates can be beneficial in everything from reducing chronic low back pain to reducing stress and anxiety.

Why is Pilates so popular?

"Almost the entire boutique fitness trend over the past decade was driven by harder, faster, louder," New York Pilates founder Heather Andersen told "GMA." "Everyone from beginners to athletes maxed out in class, resulting in injuries and burnout. Some boutique fitness studios even used reformer-lookalike machines and movements that were intended to push students to the limits."

Alternatively, Andersen championed how Pilates can be an "extremely rewarding full-body, low-impact workout."

"It's a smarter way to strengthen your entire body, tone your muscles and get fit," she said. "It's an efficient practice and it's a workout you can do every day."

Experts have also noted the Pilates rise may be partially credited to the COVID-19 pandemic when many people shifted from high-intensity workouts solely focused on fitness and performance to more intentional activities that enhance the mind as well.

The ongoing rise of popular social-sharing platforms such as TikTok, YouTube and Instagram has also increased exposure to the workout and helped with its resurgence.

To date, the hashtag #pilates has over 23 million related posts on Instagram.

Rise of modern-day Pilates boutiques

Modernized boutiques and offerings have also sprung up along with the growing interest. Andersen credited some of the success of her airy, bright New York Pilates studios to the company's use of social media and making it appealing to downtown New Yorkers. "Pilates is not a trend, it's a movement," said Andersen.

She continued, "By creating beautiful environments that feel more like homes instead of gyms, NYP has created a space that people want to work out in. You'll feel like you're working out in the apartment of your dreams. We hire the absolute best 400-hour certified Pilates instructors and students have started realizing just how effective Pilates can be."

Another Pilates-focused fitness chain, Solidcore, has gained a lot of attention thanks to digital content creators sharing their experiences at different locations.

"Solidcore differentiated itself from all the rest because we provide it all -- an effective workout, a mental and physical challenge, a space where you can focus on yourself and an incredible community," Solidcore CEO and President Bryan Myers told "GMA." "If you're looking to see results right away and feel supported and challenged, then there is no better place to be than Solidcore."

He added, "With the lights down and music up, you'll find a stronger version of yourself by the first song change."

Why is Pilates so expensive?

With many Pilates pros, come a few cons. Many people have called out the price that can vary anywhere from $35 for a single group class to upward of $120 for one-on-one sessions.

"Our class sizes are much smaller -- generally about 15 people -- allowing our coaches to provide individualized attention, form correction and accountability to ensure that you get the most out of your 50 minutes -- an investment in yourself and your future strength," Myers said. "Our pricing allows us to deliver this small group model while also attracting and retaining the best coaches in the industry."

Ife Obi, a certified Pilates teacher, personal trainer and founder of Brooklyn-based studio The Fit In, explained to "GMA" that so much of the pricing is influenced by keeping up with the current market rate as well as high associated costs for certifications as well as purchasing equipment that can total anywhere from $5,500 to $9,000 -- and doesn't include any continuing education.

"While the prices are getting pretty ridiculous, there is in-depth anatomy, alignment, equipment and movement knowledge that you have to know in order to be a quality teacher," said Obi. She also highlights that much of the in-depth knowledge isn't included in standard personal training certification and can pack on an extra $1,000 in costs.

"And because of this, you generally don't teach more than six people in a group Pilates equipment class -- whereas in other modalities you can pack 30 or 40 people into a room because there's not as much attention to detail," Obi added. "But, you still have to cover the costs of the studio."

Obi also mentioned that most Pilates studios in New York have opted for affluent neighborhoods, which results in higher rents and higher overall costs for sessions.

Why is there a lack of diversity among Pilates studio owners and participants?

Obi, who is a woman of color, explained that Pilates has been inaccessible to many people of color for a number of reasons.

"From the beginning, it was seen as a modality for soldiers in Germany, then eventually dancers and celebrities in the U.S.," Obi said. "You didn't really see us in those groups and in turn, you didn't really see us in Pilates."

First-generation Pilates teacher Kathy Grant, who was Black, studied directly under Joseph Pilates, but outside of her, master trainer Lolita San Miguel, who is Puerto Rican, said there weren't many other advocates pushing to extend access of the method to people of color, according to Diversity in Pilates.

Liz Polk, co-founder of Speir Pilates, attributes the lack of representation to an underdeveloped pipeline of Pilates professionals and a gap in financial resources and support for Black-owned fitness businesses.

"There are so many amazing small Black fitness entrepreneurs out there, but their ability to grow and scale in a competitive way is severely limited when the funding is not available to them and they, instead, need to use their personal savings and/or money from friends and family to bootstrap the business," said Polk.

Polk said that on top of the complexities of raising capital, she said the pipeline of Pilates professionals is not diverse, classical training and certifications is only being offered in select locations, and there are high costs and many months of dedication and apprenticeship required to open a Pilates studio -- which can be difficult for anyone who still has to work a full-time job or doesn't live nearby.

"At Speir, we are actively addressing this pipeline issue by sponsoring trainees from underrepresented communities and seeing them through certification," Polk said. "We've even offered our trainees open positions at Speir during their certification process. To date, we've sponsored the certification of several Pilates instructors and we plan to scale our training and certification programs to truly make a positive impact on this pipeline issue."