CINCINNATI — Group exercise strength classes are among the most popular classes offered at Revolution Fitness in Cincinnati. The facility offers full memberships to the gym as well as single-class or multiple-class punch cards. Of the more than 50 classes offered, about half include some type of strength programming, giving members two to four strength classes to choose from each day. And the classes fill up fast.

“People love them,” says Mary Beth Knight, president and owner of Revolution Fitness. “Strength training is becoming more popular thanks to the increased awareness of its effect on metabolism and connection to bone density.”

The use of dumbbells and handweights is up more than 25 percent, according to 2009 research from the Sporting Goods Manufacturers Association (SGMA). Additionally, more than 40 percent of free weight users in SGMA's research were female, a change from the past when most users were male. Traditionally, most group exercise participants are female.

So, are weight machines and free weights becoming more popular because of group strength training classes? Or is the growing use of strength equipment boosting the popularity of these classes?

Mike May, director of communications for SGMA, says it's a bit of both.

“Yes, the growing use of strength equipment is increasing the popularity of group strength classes,” May says. “The existence of group strength classes adds diversity and appeal to individual strength equipment workouts.”

Jay Blahnik, IDEA Health & Fitness Association group exercise expert, says the answer may have more to do with personal preference than anything else.

“People that work out with weights in the weight room are more likely to find group strength classes less intimidating,” Blahnik says. “And people who take group strength classes are likely to find the weight room less intimidating.”

Some people prefer strength training by themselves or with a partner, Blahnik says. Other people are only motivated to do strength training in a group setting while some people cross over and do both, he adds.

“In the end, both ways of training for strength support and promote the other, but the end choice of who does what is more based upon how people like to train,” Blahnik says.

Trademarked and pre-choreographed classes, such as strength-based BodyPump, also have played a role in increasing the popularity of strength training, says Les Mills International spokesperson Nikitin Sallee.

“Overall, group exercise is growing considerably faster than the use of free weights and machines, so it may well be that group exercise is taking the lead in driving people to strength training,” he says.

HealthTrack Sports & Wellness in Glen Ellyn, IL, does not offer Les Mills classes, but 20 percent of the club's group exercise classes are strength classes. That hasn't always been the case, though, says Cheryl McDermott, group fitness director. When the club opened in 1997, cardio classes were popular, and she had a hard time convincing people that they needed to participate in strength classes, too. Now, strength classes are the second-most popular class next to group cycling.

Despite the gains in popularity, strength training is not nearly as hot as it should be, says Wayne Westcott, fitness research director at Quincy College in Quincy, MA.

At any given time, at least five times as many people are using cardio equipment in a club than are using strength equipment, he says. People know that cardio training can help reduce their fat, but most people are not aware of strength training's benefits. As we age, people lose muscle, which decreases their resting metabolic rate about 3 percent for every decade, Westcott says. People don't know they should be concerned about replacing that muscle.

One way to fix that is creating a hybrid fitness professional who is trained as both a group exercise instructor and a personal trainer, says Bob Esquerre, certified fitness professional and owner of Esquerre Fitness Group, Boca Raton, FL.

“Introducing members to the strength floor is the biggest obstacle for the health club industry,” says Esquerre, who recently worked with TCA Holdings, Chicago, to add these hybrid professionals to its staff. “In a group, members feel more comfortable, but you need a way to make that transition and get them introduced to strength.”

A hybrid professional can teach members in a group exercise setting, then get them acquainted with the weight room through a personal training one-on-one or a small group session, Esquerre says. This scenario ultimately helps increase personal training sales, group exercise participation and retention.

No matter how clubs do it, strength is an integral part of any club, and finding new ways to engage members is key. Knight frequently adds new types of strength classes to Revolution Fitness' schedule.

“Our members expect it,” she says. “They like new classes and new ways to challenge themselves. They also like new equipment. Facilities need to have something new each year to keep their members engaged.”