Fitness historian, author, and group fitness instructor, Natalia Petrzela explains the historical and cultural significance of the strength training boom.
Take a look around the Club floor, and you’ll find nearly every workout bench taken and a line of people waiting for a squat rack to free up. Many of the treadmills and ellipticals across the room, though, will be sitting empty.
But people haven’t always been so hyper-focused on building strength. Ahead, learn how resistance training went from being an inferior form of exercise to a popular individual workout and group fitness program, as laid out by Natalia Petrzela, an associate professor of history at The New School, the author of FIT NATION: The Gains and Pains of America’s Exercise Obsession, and a former Equinox Group Fitness instructor.
Strength Training’s Downfall and Comeback
Throughout much of the 20th century, exercise was synonymous with lifting massive, heavily loaded barbells, but pumping iron was pushed to the back burner around 1970, says Petrzela. At that point, the mantra was simple: Cardio is king. “[That’s] because it's really associated with weight loss, but I think we often forget it's also associated with heart health,” she notes. “For a long time in the middle of the century, there was a ton of concern that men who were working at desks all day were susceptible to heart disease.”
By the ‘90s, strength training was making its way back into popularity, thanks to its benefits for bone health and metabolic rate, says Petrzela. (Remember, weight loss has always been a driving force in the fitness industry.) Still, the prevailing message of the time was to have minimal body fat, and for women in particular, “bulking up” was to be avoided at all costs. The method to achieve that end? Once again, do cardio, she says. “I think all of that [pressure] serves to limit the popularity of weightlifting, even though the science is there [to support] it throughout the nineties,” says Petrzela.
Lately, though, fears of gaining muscle have begun to fade away, and exercisers of all genders and backgrounds are embracing the strength and muscle benefits that come with lifting heavy weights. In the age of high-tech fitness systems that provide countless data points to inform your workouts, says Petrzela, the simplicity of strength training can be freeing.
The Rise of Strength Classes
Due to the long-lasting influence of women’s societal-induced fear of “bulking up,” group fitness classes, such as dance aerobics, were initially choreography-driven, women-centric spaces, says Petrzela. “Because of the culture we live in, girls and women are more accustomed to growing up having gone to tap, dance, or ballet,” she explains. “Dance is often coded as feminine, so it made sense that women were going in [to classes.]” Group workout classes were also advertised toward women, with female instructors and names along the lines of “the skinny jeans workout” or “the Brazilian butt class,” she notes.
Around the same time that strength training came back into the mainstream and aerobics hit its peak, group fitness classes started to become geared toward men, says Petrzela. Soon enough, men were taking martial arts, cardio kickboxing, interval-based step aerobics, and indoor cycling classes, the latter of which appealed due to its ties to sports, lack of choreography, and primarily male instructors, she says.
In the 21st century, though, men and women don’t work out that differently; about 35 percent of men and 26 percent of women in the U.S. strength train at least two times a week, according to 2020 research. Women made up 47 percent of USA Weightlifting’s athlete members in 2018, and strength training was the most popular workout of 2022, the second year in a row it earned the top spot, according to data from ClassPass. And group fitness has adapted to account for this shift. Now, “there are these [class] formats which are much more universally welcoming,” says Petrzela. “It's no longer complicated choreography or highly gendered language, and part of what they're offering is strength training that’s also scalable to lots of different bodies.”
One such class: Equinox’s Stronger series, which launched in September 2022 to give members of all fitness levels the chance to train for strength gains in a group environment, says Chris Vo, Equinox’s director of group fitness programming and Stronger’s project leader. The 45-minute classes are cardio-free, low-impact, and involve using heavy weights to build strength throughout the entire body. What’s considered “heavy” all depends on the person, and the goal is to choose a weight that you can use for a maximum of six reps for a given exercise. “This class will challenge the fittest of fit, but also provides a path for even the most deconditioned to become stronger with every set,” says Vo.
Importantly, the classes are intended for individuals of all genders, and members who identify as female make up more than 60 percent of Stronger class participants, says Vo. “We are leading the trend toward a stronger body for everyone,” he notes. “The myth that strength training makes you big and bulky is simply not true. Strength training unlocks your ability to maximize your potential for all the other things you do: running, cycling, boxing, yoga, skiing, rowing, hiking, fishing.”
Why Try Group Strength Classes
Group strength classes not only help you get closer to meeting your fitness goals, but they also make your workouts feel less like a chore. “Aside from the universal benefits of strength training — stronger bones, maintaining joint flexibility, metabolic benefits, better balance, potential to increase muscle mass — participating in a Stronger class builds a sense of community, which ups the fun, keeps you accountable, helps to keep you motivated,” says Vo. In fact, when you have a greater perception of groupness during an exercise class, you’re likely to experience more enjoyment and pleasure and rate your perceived exertion higher, according to research published in the journal Sport, Exercise, and Performance Psychology.
To newcomers, this community can make resistance training feel less daunting. Figuring out how to deadlift or bench press a barbell for the first time — and potentially failing your reps — under the watchful eyes of other members can be so intimidating, a beginner may skip over weightlifting. However, “classes are a powerful way to get some instruction without the isolation of being on your own,” says Petrzela.
Ultimately, well-programmed strength classes can help ensure you’re continuously progressing toward your goals. “Members who strength train on their own typically do the same exercises week after week with little variation,” says Vo. “This can lead to plateaus in strength gains and a lackluster outlook to fitness in general. [Stronger’s] creative training patterns and timed protocols will teach you new things to do on the weight floor.”