This is not your usual workout. This is a heart-pounding, ego-bashing test of your limits. Why put yourself through so much pain? Because if you can do this, Bucko, you can do anything.

Ever had the urge to go through Marine boot camp? Just for a while? Without the yelling? On a Southern California beach?

The first moments are paradise: skimming the sand under a brilliant morning sun, lungs bursting with sea air, perched atop a silky sand dune doing push-ups--each one rewarded with a glimpse of limitless Pacific. Then the work begins: pull-ups on an overhead bar, hitting the ground for eight-count body-builders, push-ups on an incline, hanging like a chimp for body-pulls. Shimmy up a slanted pole? Dangling at the bottom is about the best we can manage; by now, all ego has vanished. Twenty forward stadium hops, a five-minute jog around the circuit, 10 squat-jumps in place.

And it's not yet 9 a.m. At this hour on "work" days, the executives assembled on Santa Monica Beach would probably be launching into their first phone calls. This bright Saturday morning, they're already sweating as if they've run a four-minute mile. When we hear, "That was one, we're going for three," even the strongest have to fight back a tear.

"It takes you to a different level--whether you want to go there or not," admits Teri Carcano, an advertising sales manager for Turner

International.

Today, two L.A. executives--31-year-old Carcano and 47-year-old business manager Robert Matthews--have surrendered their bodies to a day of elite-level, outdoor, one-on-one instruction, the kind endured by the laywers, vice-presidents and cpas who work out regularly with Adventure Fitness Training. Their taskmasters are Valerie Ringo--triathlete, marathoner, equestrienne--and Tony Molina--former Amphibious Reconnaissance Marine, those fellows who scuba dive behind enemy lines to see if it's dangerous.

"Work us flat out for three or four hours," Carcano and Matthews implore. They let Ringo and Molina choose the disciplines. Brave souls, these two, since Ringo and Molina race the Eco-Challenge, a yearly event covering 500 kilometres of extreme terrain by hiking, rappelling, horseback riding and white-water rafting for eight days and nights--non-stop.

"If you can do this, you can do anything," Ringo urges, her firm hand guiding our backs as we struggle to clear the parallel bar. "For some reason, getting fit is one of the most unattainable goals for the general population. Most people put it on the back burner," she calls back to us laggards as she sprints down the beach. "It never seems quite important enough." She's talking; we're gasping for breath. "If you can commit to doing what it takes to bring yourself to this high level of fitness, you can make $1 million. You can start your own newspaper. You can accomplish anything."

"I think a lot of people begin this for the physical benefits, without anticipating the mental advantages," says Carcano, a veteran of Adventure Fitness Training's most gruelling course, an Eco-Challenge-style weekend. Here she has witnessed the effect of supreme physical exertion on her compatriots. "In these extreme situations, you come to a point where your brain takes over. Your body can do anything your mind tells it to do." For Carcano, the parallel to business is clear. "Senior executives get to their positions for a reason. They're sharp, they're smart, they've played a very competitive game. Doing this takes you to the top of your form."

Our three rounds of training complete, we're collapsed on the shore in what feels like justifiable exhaustion, sand radiating warmth through our limbs like a heating pad. We would probably have lain inert for a week if Molina and Ringo hadn't coaxed us toward the hills.

A five-minute drive through some of L.A.'s priciest real estate brings us to Westridge Canyon, an enclave of bike and hiking trails with stunning views. On the beach, we had grazed the edge of our endurance. On this mountainside, we would challenge our fears.

When Ringo and Molina said "biking," we pictured tar-smoothed lanes in the park. "I never thought this would be scary," laughs Matthews. At 47, Matthews, a first-time participant, is struggling vainly to put his bike into forward motion on a steep, gully-riven slope. For long moments, there is no discernible progress.

"What you don't want," Ringo entreats gently, "is to walk away without completing the task to the best of your ability." Matthews carries his bicycle across the widest crevasse, and with monumental effort pounds butt onto seat and legs into pedals. Remarkably, the bike lurches to the top of the hill. Hearts pumping, T-shirts sweat-stained, each member of our now-ragged band feels like Hercules--until it occurs to us we must descend that same monster slope. Next surprise: Going down is decidedly more frightening than going up.

"Having the fear

is normal," Ringo assures us, obligingly demonstrating the brakes. "It's how you overcome the fear that's important." Here is a challenge we can't face in the gym. As each of us summons the courage for our downhill "flight," Ringo stands by with relentless patience, at times offering a bit of technique, at times simply waiting. It is sheer mental strength that propels Matthews through the wall of dread; a push that comes not from his muscles but from his spirit.

"Going down the hill was cool," he grins at the bottom, covered in mud and glory. "It was a fear I could deal with right then and there," a triumph he feels might come in handy Monday morning. "Sometimes I'm afraid of a business situation, or of meeting new clients. But I find that if I go after the fear, like going down the hill, it becomes fun. If I stop, I stagnate."

Moments after his first terrifying run, Matthews is struggling up the hill once more, thinking this might be something he could do with his clients: producers, writers and directors on such shows as Beverly Hills 90210, Star Trek: Voyager and Mad About You. "In L.A., people don't like to come to offices," he says. "We do business in more social settings, such as restaurants, tennis courts or bowling alleys."

"To a certain select group of people," Carcano adds, "the more adventurous an activity, the more appealing it is."

After conquering the mountain, coasting back down the dirt trail feels like a jaunt in the park. We've gained so much confidence we nearly forget the danger. "Pick your line," Ringo cautions. "Look out in front of you--don't look down. Choose the path you're going to take." Good advice in any situation. "And no matter what happens," Ringo calls as we disappear around the bend, "don't stop pedalling."

SWEAT THE DETAILS

Adventure Fitness Training Located at 1527 Yale St., Santa Monica, Calif. 90404. Tel: (310) 315-0454. Activities include: night hiking, mountain biking, log endurance, canyoneering, horseback riding, ascending and rappelling, kayaking, bungee jumping, stroke workshop and overnight camp and climb. Package rates and group rates are available.

Cost/time/benefit analysis

Adventure Fitness Training

Cost $75
Time 90 minutes of one-on-one training
Benefit A surge in self-confidence