LOUIS STACK sees the future of exercise: Dutiful employees sequestered in their cubicles, each seated on a Swiss ball—a kind of latter-day Hippity-Hop sans handle—sipping coffee, typing reports, and making phone calls. Hasta la vista, health clubs; buh-bye, Tae-Bo. No, Stack's not some interior-design wing nut. Rather, the Calgary-based former World Cup skier champions Swiss balls, along with a dozen or so other devices sold by his company, Fitter International Inc., as the keys to what's known as functional training. Stack is living proof that it works. After skiing for Canada's national team in the early nineties, he retired for good in 1995, replacing traditional gym time with some unorthodox training: sitting on a Swiss ball at his desk all summer. When he hit the slopes that winter, he'd catch an edge, feel sure to fall, and then smoothly recover. "All my buddies said, 'What have you done? Your skiing has improved so much!'"
Sounds like an infomercial, but this happens to be one with solid research behind it. Functional training develops proprioception—your body's ability to sense where it is in space—by calling on exercises that mimic the dynamic movements specific to sports such as skiing, biking, and surfing. When Stack first introduced the Pro Fitter, a sliding- platform device for skiers, back in 1985, selling it was tough. "The fitness industry was too focused on single-station machines that isolate muscle groups," Stack says. "Few people were trying to work the balance and strength system as a whole." The breakthrough came gradually. Fitter's sales started to boom in the early nineties thanks to increasing use by physical therapists and coaches, and by the end of the decade functional training had gone mainstream. It's now embraced by everyone from the U.S. Ski Team to Australian professional surfers.
At the center of functional training is some uncomplicated and delightfully dorky equipment: Swiss balls, wobble boards, weeble boards, balance boards, medicine balls, and their kin (see Field Test, right). This kind of equipment, proponents stress, fills the gap between strength and endurance training by programming the brain for sport-specific moves while simultaneously developing joint stability and range of motion. "When you use a fixed-axis machine in a gym, the muscle you develop is aesthetic, not functional," says Paul Chek, a clinical exercise specialist and head of the Chek Institute, an exercise facility in Encinitas, California. "The muscle recruitment is different than when you're weight lifting. In, say, rock climbing, when do you ever pull on a bar that moves toward you?"
Suzanne Nottingham, a Mammoth Lakes, California-based trainer and spokesperson for the American Council on Exercise, suggests folding functional training into regular weight and endurance routines. Do balance exercises for a few minutes just after your warm-up, and throw in two other brief sessions during your workout. "It's better to have more frequent but shorter exposures to balance training," she says. Weight lifters can add one set of presses or dumbbell fly lifts on a Swiss ball, or squats on a rocker board; try it first with reduced or no weight and build up to heavier pound-age (with a spotter, of course).
The exercises (see below) can be challenging because they demand highly refined balance, so Nottingham insists that novices warm up with the following practice moves on a stable floor without equipment: Stand with your feet shoulder-width apart and your weight distributed evenly. Keeping chin in line with hips, slowly shift your weight to the right leg. Drag your left foot behind your body with toes pointed down and with your arms out for balance, keeping most of your weight on the right foot. Now raise the left foot. Repeat with the opposite leg.
With some of his athletes, Chek has foregone muscle-isolating machines in lieu of a functional-training protocol involving moves similar to old-school calisthenics. After all, how much do machines re-create the complex motions of whitewater kayaking or snowboarding? "You got it, baby! Zero!" says Chek. "Why stick with the first- grade mathematics of the rowing machine when you can prepare for the trigonometry of real outdoor sports?"