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Swim, bike, run. Repeat.

Triathlons are the rage, but still require training, sweat, and discipline

It's the talk at the backyard barbecue, the chatter in the gym locker room, the come-on at the bar. Competing in one of the thousands of triathlons around the world is the fitness marker of our times, what running marathons was in the '90s. With triathlon clubs proliferating and mentions on TV shows like "Grey's Anatomy" and "Scrubs," running a triathlon has become trendy.

So what does it take to compete? That depends on the goal, say local fitness instructors. But for most amateurs, who fit triathlon training around work and family, the most popular triathlon is the sprint -- a half-mile swim, a 12.4-mile bicycle race, and a 3.1-mile run. Those are attainable goals, say trainers, for those looking to stay in shape and have fun competing.

"If you're already athletically in shape, it's no big deal," says Diane Hamilton, a certified trainer at Webb's Pro Fitness in Norwell.

That doesn't mean it's easy. A sprint triathlon is more than just the sum of its parts, trainers say. "It's a sport with some complexity," says Steve Kelley, who works for USA Triathlon developing junior triathletes.

Drew Gustafson and his partner Nakeeya Deas of Morpheus Personal Training in Marblehead suggest a 16-week training course for those planning a sprint triathlon. They recommend breaking down training so that one day a client might bike for an hour and a half, and the next day run, and the next, swim.

Although it's important to train in all the disciplines, special exercises do help, Gustafson says. He adds sprints and uphill runs to running routines. He often has clients do explosive jumping moves up onto small platforms to expend a "huge amount of force for a short time."

While longer triathlons are more about endurance, as well as getting enough water and nutrition while competing, even the shorter races require intense stamina. Core work, such as Pilates, is great for strengthening the back and abdominal muscles needed for endurance competition, Deas says.

Gustafson, ranked fifth in the nation in BMX bike competitions, helps clients build endurance in biking. He works on efficient pedal stroking and often has them wear monitors to check that they're pumping hard enough to keep the heart rate up.

Special exercises can also help with swimming. Besides swimming laps year round, he has clients practice strokes and breathing techniques on an exercise bench.

The open-ocean swimming, though, is often the trickiest part of a triathlon. Karen Ghiren, who owns Wellness Works in West Newton, says open ocean swims "can be frightening" to those used to pools. She recommends swimming in Walden Pond or another large body of water to learn how to site the buoys, or judge distances.

New triathletes can also be caught off guard by the sheer number of contestants in a race, says Hamilton, who for several years taught a six-week triathlon training program for women. When several hundred people all start swimming at once, the more aggressive push over the slower ones. "People are swimming on your back and pushing you down," Hamilton says. She suggests keeping calm, treading water, or breast stroking until the crowd clears.

Transitions from one part of the race to the next can hurt both timing and energy levels. If you're wearing a wet suit, for example, getting out of that and into shorts, shoes, and socks takes time. "You can't wait until the race to practice that," she says. The switch from the long bike ride to running can be another rough transition for athletes.

Choosing the proper equipment is also important, Gustafson says. The right bicycle with a light frame and such features as extenders to rest hands and arms; light, well-fitting running shoes; and the right wet suit are all musts. A wet suit adds buoyancy, as well as warmth in the cold ocean water.

Triathlons are recreational, but for some athletes there's also a social element, with clubs, websites, and get-togethers for people looking for training partners. But getting serious about objectives is important, too.

"We're here for you to facilitate you getting to a certain goal," says Deas. But what's most important is for people to be honest with themselves. There's a risk in "pretty much anything," she says, but with diligence almost anyone who wants to can compete. She also emphasizes nutrition.

"If I'm training someone for a triathlon, I'd suggest cutting out alcohol entirely," Deas says. "It's a short-term goal, and you don't need the sugars and carbs."

The results can be worth the training, sweat, and discipline required. As Hamilton says: "The very first time, there's nothing like that emotional high." 

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