If you’re pushing back-to-back gym classes without seeing major results, try this: Australia’s most hyped workout class that just recently hit U.S. shores. Called F45 (short for function 45), the 45-minute, high-intensity, circuit-style technique has a reputation Down Under for transforming bodies in just a matter of weeks—mine included.
I first tried F45 in 2013 while living in Sydney, back when it was still a relatively undiscovered concept on the Aussie fitness studio circuit. Classes had recently launched at a friend’s gym, so I felt obliged to give it a try. “It’s really hard, but the time goes by crazy fast,” my friend promised as I agreed to a two-week free trial.
Almost four years later, I remember three things from that first class: My glutes burned so hard that I avoided stairs for three days, the 45-minute session whipped by in what felt like 20, and I scheduled five more workouts that week on the train journey home. It was just one class, but I was already hooked.
Over the following couple of months, I recruited friends to work out with me, all of whom rapidly fell under the F45 spell. I started attending daily, jumping out of bed for the 5:30 a.m. class, so strong was my addiction to the workout. In the four short years since it launched in Australia, F45 has become a favourite spot to ’gram among the international fitness blogger crowd and has rolled out 750 studios across 26 countries. Today, it’s where almost every young Aussie celeb, model, and Instagram star works out.
There are several different classes on the roster, but each high-intensity, interval training–style circuit follows a winning formula that turns casual gym goers into bona fide F45 fangirls. For example, you move quickly through exercises, spending about 30 to 40 seconds at each station while large screens count down the time as gif-style graphics clearly demonstrate the movements required at the station. This means you always know what’s coming next and can push through the workout knowing the next break is just seconds away. The variety helps deter boredom too: One minute you could be sprinting on the rowing machine, and the next you might be doing assisted chin-ups or box jumps.
Lucas Catenacci, co-owner of the freshly launched Flatiron studio, says members who commit to at least three sessions a week experience rapid results: “Typically, body composition changes in one to two weeks [with a] decrease in fat and increase in muscle, and dramatic changes in four to six weeks,” Catenacci told me. Specifically, he’s regularly seeing weight loss in excess of 20 pounds and significant body composition changes in just eight weeks of regular sessions.
Like most good stuff, F45 memberships aren’t cheap: A single session costs $40 (or $35 each when you pre-buy 10), while a month of unlimited workouts is $450. Right now, F45’s also kicking off an eight-week challenge that offers a few discounts. Yes, it’s pricey as hell, but if you’re looking to tone up, well, the results speak for themselves.