With thousands of Americans listing "get in shape" or "exercise more" at the top of their New Year's resolutions, its no wonder that U.S. health clubs and gyms are in the midst of what has historically been their high season.

According to the International Health, Racquet and Sportsclub Association, January is the leading month for new membership sales — 12.4 percent of new members sign up in January, with the first three months of the year accounting for one-third of the total yearly club memberships. The IHRSA estimates that 10 million Americans will join a health club in 2006.

But whether you're embarking on your first foray into fitness or returning from a long absence, you may be in for surprise — particularly if you're a woman whose last exercise experience involved jumping up and down in fluorescent leotards.

The American Council on Exercise says fitness is no longer just about pumping the heart to beat faster or acheiving rock-hard abs. Following its annual survey of 50,000 fitness professionals, ACE says the focus in fitness in 2006 is "functional fitness," an approach concerned less with how good your body looks and more on how well it works, with workouts designed to get your heart and muscles in shape to perform the physical tasks they are called on to do every day.

"People are finding exercises that help with everyday activities and prevent injury as they age," said Dr. Cedric Bryant, ACE's chief exercise physiologist.

Forget the fancy footwork of traditional aerobics classes; the big buzzword is "back to basics": traditional moves like push-ups and exercises that condition the body's core — the mid-section, lower chest, back and upper thighs. These core muscles are the body’s center of power and provide stability for body movement in exercise and everyday activities. By training the core muscles, postural imbalances can be fixed and injuries prevented.

While the class roster at most gyms will still feature plenty of specialty options like striptease aerobics and yogilates, expect to see a lot more offerings branded with names like "Boot Camp," "Basic Training" and "Core Conditioning."

"Why use weights or machines if you can't even do a push-up?" says Todd Scott, founder of Platoon Fitness, a Rosemount, Pa., based chain of fitness "boot camps" with 11 locations throughout New York and Pennsylvania. Platoon's program, he said, is designed to use the body "the way it's designed to function."

Back to Basics

This "back to basics" approach is not so much a new trend as an exploding one that has traditional health clubs and gyms adapting their programs to keep up with an American fitness consumer that has rediscovered sports and athletics. One-time gym rats are increasingly abandoning their treadmills and stair steppers for "real" activities like biking, running, swimming and training for competitive events.

One of the most popular fitness activities among women right now is not just Pilates or step aerobics, but triathlons. According to USA triathlon, female membership has increased from 11 percent in the early 1990s to around 29 percent today. The Road Runners Club of America says most of its new membership over the past decade has also been driven by women. Overall, between 150,000 to 200,000 people in the United States try a multi-sport event each year, and those numbers keep growing.

Interviewed in July about the growing ranks of women leaving their aerobics classes for triathlon training, Kathy Davis, the CEO and executive director of IDEA Health and Fitness Association, a membership organization for aerobics instructors, personal trainers and other health and fitness professionals, said that gyms were feeling the shift. Fitness directors, she said, were now organizing and advertising training sessions for local running events and working to position their gym as a place where people could prepare for their sport.

Boot Camp Boom

This kind of back to basics, athletic-type training requires a different level of mental commitment and discipline, and with more and more people choosing this road to get in shape, it's no wonder that exercise "boot camps" are also popping up across the country.

Typically, these boot camps follow a military-style circuit of drills that might include running, jumping jacks, push-ups, squats, sit-ups or even obstacle courses. And the 2005 IDEA Fitness Programs and Equipment Survey shows boot camp classes on the rise, with 35 percent of facilities offering indoor boot camps and 16 percent offering outdoor camps.

"Boot camps try to get out of the conventional type of environment and back to the elementary aspects of physical training, emphasizing the psychological and disciplinary aspects of fitness," said ACE's Dr. Bryant.

Scott, whose Platoon camps have been around for nearly 11 years, said TV shows like "The Biggest Loser" on NBC and VH1’s "Celebrity Fit Club" are contributing to the popularity of boot camps with their focus on weight loss through fitness and diet.

Michael Rutherford, president and trainer of Boot Camp Fitness, founded his camp in 2000 after 25 years in the fitness industry as a conditioning coach at the college level running athletic performance camps. His goal with Boot Camp Fitness, he said, was to create a functional fitness program.

"For aging athletes, it's very useful for improving balance and hip mobility," Rutherford said. "Many times certain muscles have been ignored so there are slight imbalances or weaknesses."

Which is why boot camps like Rutherford’s adapt techniques from the grueling military camp style to one any ability or age can participate.

"Boot camps are for all levels of fitness," explains Rutherford, whose camps take place in the suburbs of Kansas City. Rutherford’s camps will often have middle-school age kids, college athletes and grandmas.

Rutherford scales the workouts based on ability, with push-up variations that might have some clients working at the wall while the more advanced students do decline push-ups. His approach, he said, is more that of an encouraging coach than a drill sergeant’s.

"I’m just looking for your best effort."

But Scott of Platoon still considers boot camp, "the mother of all workouts."

"It’s a tough workout and it’s the beginning… It’s how legions of armies have trained for years," he said. "It’s definitely not Curves," he added, referring to the fitness club for women.

Platoon’s "recruits" will find themselves working the lower body on Monday and Thursday and the upper body on Tuesday and Friday. Wednesday is reserved for the cardiovascular workout. Although the order of focus never changes, Platoon, like other boot camps, like to keep things fresh by creating a variety of ways to incorporate their exercises. For Platoon instructors, this means using a combination of the 1,115 approved exercises that Scott says, "Have the least amount of injury and will build a solid foundation increasing speed, quickness and power."

While things may seem serious at Platoon, they try to keeps things "tongue-in-cheek," he says detailing what often happens when participants are no shows.

"Platoon is structure and discipline and real life consequences if you don't do it. People wonder where you are if you don't show up," says Scott.

"First we’ll call you if you didn’t make it, then we may send you a postcard of fat people or a coupon for Krispy Kreme doughnuts," he says.

For those who continue to skip workouts, Scott says they might call a spouse or co-worker and come to the offender’s home or workplace, bringing the class along to join in the harassing by doing a workout on the front lawn.

Rutherford also says that the camaraderie of the group is what helps participants stay motivated and focused, not to mention, for some it’s their only chance to get outside when the weather permits.

The discipline reaps results say both Scott and Rutherford. "The whole idea is to provide a really regimented structure. If you show up, you’ll see great results," says Rutherford.

And for many looking for an exercise routine at the start of a new year, boot camps may just provide the structure necessary to stick to a plan.

But don't be deterred if drill sargeant trainers or boot camp style workouts don't suit your style. New trends often catch on because they produce new results, but the most important aspect of your workout is that you like it enough to do it regularly—provided it is producing fitness results. If you're 2005 work-out is still working for you, there's no reason not to stick with it. ACE says that simple exercise habits, like a walk a day, will remain popular in 2006.