The ubiquitous red, white and blue logo. The'Team training, life changing'motto.No mirrors. No microphones. No egos.

You probably know all of these things about F45 - even if you've never set foot in one of their gyms.

Everyone knows someone who does F45. And they're usually addicted to it.

Watch: Here's what horoscopes look like when they're working out. Post continues below.

From the endless celebrity endorsements and the 'cult' following, to the impressive Wall Street debut and the millions upon millions of dollars - the fitness chain has been a bone fide success story.

But in recent times, F45 started losing its momentum.

The stock prices tanked. The co-founder and CEO stepped down and sold their stocks. Franchises closed. People lost their jobs.

Despite having such a loyal following, at least 11 gyms in Australia having closed down unexpectedly.

And it's not only the franchises that are taking a hit, but the customers too. Many have reportedly been left out of pocket after recent collapses, with some owed up to $1000 for upfront membership payments.

Jane*, who has been an F45 customer since 2017, has been waiting for her refund for months. In an interview with news.com.au ., she said her local F45 gym in the Melbourne suburb of Werribee shut down in August last year.

"We were so upset," the 39-year-old told the outlet. "They owed me just over $1000 and I thought, ‘when am I going to get my money back’?"

Some of the franchises have even been left to sell off gym equipment to cover their losses.

As Jane shared, the gym started showing cracks at the beginning of last year, when there was minimal equipment available to complete workouts.

"The videos had rowing machines and skiing ergs, and… different sort of bikes, we never got those," she said. "We got suspicious."

It was around this time that her gym had promoted an offer of paying $1000 up front for six months.

So, what's happening?

Below, we take a closer look at the rise and fall of F45.

How F45 became so successful.

Functional 45 (better known as F45) is the worldwide Australian-born exercise phenomenon that went from Sydney to New York, opening up thousands of franchises and making lots and LOTS of money - it's a truly great business story.

Co-founded in 2013 by former Sydney banker Rob Deutsch and Adam Gilchrist (not to be confused with the Aussie cricketer), it was based on a simple idea - to modernise the traditional gym format with a 45-minute high-intensity, group workout.

The workout approach might sound pretty standard now, but at the time the whole thing was revolutionary ( HIIT classes were only starting to becoming a thing) - there wasn't much out there like it.

And it was an instant success.

Within the first two and a half years of operation, the fitness chain went from one gym in Paddington in Sydney's eastern suburbs to around 200 studios.

In less than eight years, it went on to sell over 2,000 franchises across 63 countries.

In an interview in 2018, Deutsch contributed the instant success to creating a "cult-like environment" which makes clients want to come back.

"We’ve created a way to get people to want to come to the gym. Our clients actually turn up," he toldnews.com.au.

"Globally on average people turn up to normal gyms once a month. At F45 people turn up more than any other offering, about three times a week," Deutsch said.

"People want an experience and they want to feel a part of a community. It’s not just putting your headphones on and throwing around dumbbells."

"Our clients become friends and they start hanging out and have coffees before and after sessions. Through this cult-like environment we have built a really strong community."

The formula to success? The high prices.

It costs $65 per week to attend the 45-minute classes. Meaning? When you’re paying so much money, you're going to want to attend as many classes as possible. Otherwise, you're pretty much throwing your money down the drain, right?

"We’re way more expensive than normal gym models and that makes people feel like they need to use the service," Deutsch said.

Tactical.

"Our clients stick us with us longer than any other gym model. On average, F45 members stay for about 18 months. Our prices are sometimes 12 times higher than a normal gym, but our clients stay for longer," he said.

The other important ingredient? Keeping the workouts different. No two classes at F45 are the same.

For example, you can go from doing box jumps and rowing to lifting kettlebells and doing pull-ups on TRX ropes. There are a certain number of stations, a trainer and a large screen with a timer showing what to do next.

This recipe is part of what the company touts as the key to maintaining results.

Along with this unique formula, there's no way you can talk about F45's success without mentioning its gigantic celebrity backing.

Since its inception, the fitness empire literally exploded in Hollywood, becoming a cult celebrity workout with a slew of A-lister fans - including Hugh Jackman, David Beckham, Nicole Richie, Mario Lopez and Cindy Crawford. https://www.instagram.com/reel/Cewh6wAh77t/?utm_source=ig_embed&utm_campaign=loading

One of the most noteworthy celebrity supporters? Actor Mark Wahlberg.

You don't have to know anything about F45 to know about Wahlberg's involvement with the fitness franchise. He's everywhere on its social media accounts. And vice versa.

In 2019, the actor teamed up with an investment company called FOD Capital to buy a stake in F45. Together, their investment valued F45 at $450 million.

Wahlberg can be regularly seen plugging the workouts on his Instagram, showing off his physique and touting F45 as his favourite form of workout.

Shortly after Wahlberg jumped on board, F45 was one of the fastest growing franchises in the world, and it experienced an incredible few years of revenue growth.

According to Superhero, the company went from making $25 million in 2017 to $93 million in 2019.

Some ridiculously big numbers.

After such solid success over such a short amount of time, things started lookingvery goodfor the fitness franchise. To put it into perspective, the rapid growth of F45 was faster than franchises like McDonalds and Subway in Australia.

What happened to F45?

But as soon as 2020 came around, something started to change.

All of a sudden, the revenue and share price took a hit, with numbers dropping to $82 million - presumably due to the impact of COVID.

Then, Rob Deutch stepped down as the company's CEO - just shy of F45 going public and making its market debut on Wall Street.

It was a shock move.

On Instagram he wrote, "As the founder of F45, I’ve had the privilege of helping build the company into one of the fastest-growing fitness franchises in the world. My time at F45 has been deeply rewarding and enjoyable. I am incredibly thankful for the business partnerships and friends made along the way."

"As some of you know, I recently (2 months ago) transitioned out of my role as CEO at F45. I still remain a shareholder. The F45 future is bright, and I look forward to watching from afar. I look to the future with optimism and wish all friends, family, and franchisees a safe journey through this challenging time. I have a sneaking suspicion we will meet again soon in the wellness space.. BE SAFE and THANK YOU for the support."

Off the back of Deutch's departure, the company went ahead with their plans to go public, appearing on the New York Stock Exchange with a $2 billion valuation.

Wahlberg and Gilchrist appeared on the floor of the NYSE to ring the opening bell.

On Instagram, Deutch praised the team for listing, writing: "I genuinely wish Adam, Mike Raymond, the incredible team, and all the franchisees the BEST as the company enters another chapter! Just awesome (ps