VERN GAMBETTA WANTS you to pay close attention. The 59-year-old coaching legend is going to tell you how to get the absolute most out of your body—and this time he wants everybody to get it right.

Gambetta's approach is called functional training, and it's based on a smart and basic principle: Athletes need to train movements, not muscles. Instead of common gym routines that isolate individual

"People need a systematic approach that keys in on the basic motions of human movement," says Gambetta.

muscles—like biceps and hamstring curls or knee extensions—functional training favors exercises that get you on your feet and replicate the multidirectional full-body motion of sports. Rather than sitting on a bench to pull or push a weight-machine bar, you'll be forced to keep your balance and engage entire muscle groups in coordination—which is exactly how they work in the real world, whether you're rock-climbing or hitting home runs. And because functional training stresses the link between your upper and lower body, you'll engage and develop your core—the locus of strength for all movement.

If this sounds familiar, it's because Gambetta pioneered functional fitness some 15 years ago. A former college decathlete, he was coaching track at UC Berkeley in the late seventies when he took part in biomechanics research conducted by Nike at nearby Shriner's Hospital. To his surprise, he learned that many of the common assumptions of machine-based strength training were false. (Quads are used to control descent, for example, not straighten your leg.) Over the next decade-plus, Gambetta began rethinking training protocols while working with the NBA's Chicago Bulls and designing new routines as a trainer with baseball's White Sox. Then, in 1991, he started offering functional-training seminars to other elite trainers. Their response was to junk many of their weight-lifting machines and persuade skeptical clients to take up seemingly old-school programs employing medicine balls, dumbbells, and resistance bands. The athletes reaped greater speed, more wins, a reduced injury rate, and less burnout.

"Vern is the master," says Jim Richardson, women's swim coach at the University of Michigan. "We used to do a lot of isolated-muscle-group movements, but after Vern came along, our athletes were immediately fitter."

"The foundation for what I do today is based on Vern's writings and those of his close colleagues," says Bill Knowles, who coached Hannah Teter, gold-medal winner in the snowboard-halfpipe competition at the 2006 Winter Olympics. "We train movements, we keep feet on the ground, we use few weight-lifting machines. It's dumbbells and balls and bands." University of Florida track coach Dan Pfaff credits Gambetta's influence for his success in coaching American Olympic high jumper Amy Acuff and Canadian Olympic sprinter Donovan Bailey.

Unfortunately for recreational athletes, though, as Gambetta's ideas trickled down to amateur gyms, they were chopped up, hybridized, and dumbed down—"15 minutes to flat abs with an inflatable physio ball!"—with no regard for a critical underpinning: Functional fitness works only as an interrelated series of exercises. As Gambetta sees it, there's little sense in trying to develop core muscles on an unstable ball before you've developed them on two feet. It's a point that he's been hammering lately in feisty postings on his blog, www.functionalpathtraining.blogspot.com, and a major theme of his seventh book, Athletic Development, an illuminating summation of his system due out this fall from Human Kinetics. "Functional training has become a buzzword for a bunch of chaotic stunts," says Gambetta, who lives in Sarasota, Florida. "It means somebody who carries a physio ball or giant rubber band and does a bunch of funny exercises. Athletes need a systematic approach that keys in on the basic motions of human movement."

What's missing from the abbreviated functional-fitness workouts peddled at many gyms is meaningful sequencing. "Progression is everything," explains Steve Myrland, a former strength coach for the University of Wisconsin who collaborated with Gambetta to develop agility workouts. "You need to ask, What am I going to do today? How does it relate to what I did yesterday? How does it relate to what I'm going to do tomorrow?"

In other words, you can't just toss a medicine ball and go back to your tired old workout; you need to commit to a whole new paradigm for the long haul. "I started training like Vern a long time ago," says Myrland. "I said, OK, I'm going to put the bands on and do the goofy monster walk. People will look askance at you for a while. And then they'll ask if they can train with you."

Be forewarned: Real functional training can be humbling—expect to be sore—and Gambetta's system requires that you adhere to a constantly evolving workout. But once you take up his six-week challenge (laid out in the pages ahead), you won't just look like a pro; you'll perform and last like one. Now let's get started.