Fit: Fighting Gravity

SIT BACK, BUT DON'T RELAX. That's the basic idea behind the Gravity Training System (GTS). The apparatus looks harmless enough — some straps on pulleys, a footrest, an inclined platform that glides along on rails — but will have you huffing and hurting in minutes.

If this rings a bell with late-night infomercial watchers, it's because for the past decade, Chuck Norris has hawked Total Gym, a similar product from the same company, EFI Sports Medicine. Unlike a lot of the junk on offer at 2 a.m., these machines (particularly the sturdier pro versions) have cred; physical therapists have embraced them for years.

Now they're popping up in classes at Body Dynamics (5130 Wilson Blvd., Arlington; 703-527-9557; Bodydynamicsinc.com). Jennifer Gamboa, president of the rehab and wellness facility, was worried that her clients were dropping their traditional fitness routines in favor of her studio's classes on the mind-body connection, injury prevention and movement quality. Or, if they were hitting the gym, it wasn't effective.

"People put a lot of time into working out, but they're often not putting enough work in," she says.

Stuffing a miniature gym into Body Dynamics wasn't the solution, as Gamboa prefers her students be supervised to ensure proper form. She also wanted a tool that raised heart rates, targeted every muscle in the body and — to appeal to her time-crunched clientele — could be effective in 30 minutes.

The answer turned out to be a product the staff already used for injured folks. Resistance on the GTS is controlled by the board's tilt. A perfectly flat board makes it easy for someone who's recovering. But as the slope increases, so does the amount of your own body weight you must move. In effect, your mass functions as the weights on traditional exercise machines.

Plus, you can tweak standard exercises to use extra muscles. Hang onto the straps and drag them upward as you do a crunch to add an arm workout. Kneel on the board, facing the top of the incline, to do curls — keeping the board stationary will force you to stabilize your abs. Repeatedly push off the footrest to send yourself up the incline while yanking the straps downward to get cardio, leg and arm action.

"It's not understandable until you get on it and try a class," Gamboa says. "But baby boomers start to jump on it and they start giggling." (By jumping, she means bouncing off the kickboard and up the slope.) Although laughs may turn to groans thereafter, many remain enthralled. Shari Pine has been hooked since January: "It was the most excruciating and fun half-hour of my life."

Her pal Terry Green likes how the workouts are scalable, so she can do the same exercises as more advanced students with modifications or at a lower incline. "When your arms are stressed, you can put your feet on the ground," she explains. Instructors encourage the super-fit, like the dancers of the Washington Ballet — who attend an annual two-week boot camp at Body Dynamics — to boost their workouts by tilting the board higher and upping their speed.

It helps that instructors play kicky music and switch up moves at a rapid clip. "Just as you can't do one more rep, you move to something else," says Pine, who has no plans to bail. The results, after all, are impressive: "I have biceps again!"

Photo courtesy Marge Ely/Express