Tackling a triathlon can be daunting, even for fitness buffs, but this training plan for swimming, biking, and running a sprint-length race, you’ll earn bragging rights (not to mention a lean, hot body) in just 12 weeks.

Triathlons used to be the domain of elite athletes. Not anymore. More than 1 million people stepped up to a triathlon starting line last year, 37 percent of them women, according to USA Triathlon.

It’s no mystery why: The swim-bike-run combo combats workout boredom and practically guarantees weight loss. Plus, the popular sprint distance (half-mile swim, 12-mile bike, and 3.1-mile run) eliminates intimidation. Just be forewarned: The feeling of accomplishment coupled with body-sculpting effects can be addictive!

Why Tri?
Watch any triathlon and you’ll see lean legs, flat abs, and sculpted arms whizzing by—all thanks to the one-two punch of endurance and resistance exercise.

The resistance comes from pushing yourself through water, which is thicker than air, and cycling up hills or into wind. Triathlon training is very balanced—it’s whole-body training.

And it shows. When you focus exclusively on one sport, you often end up strong in some areas and soft in others. Triathletes get body benefits from all three sports and are lean and fit from head to toe. Plus, the constant cardio can result in serious weight loss.

But all that cardiovascular action is good for more than just dropping a few pounds: A recent study in Radiology found that triathletes have larger, healthier hearts and a 17 percent lower heart rate (fewer beats means your ticker is so strong it doesn’t have to work as hard) than other athletes.

Your joints, tendons, and muscles will thank you too. Overuse injuries like tendinitis and stress fractures often result from weakness elsewhere in the body. Because of the amount of cross-training, triathletes build stronger muscles around all of their joints, which reduces their injury risk. Think of it as building scaffolding around a building.

A stronger body and better health starts with this step-by-stroke-by-pedal plan.

Swimming

There’s a reason even fit people end up hanging onto the side of the pool when they first start doing laps. In swimming, you use every single one of your muscles to stay afloat and work through the tension of the water. Since those muscles need oxygen and fuel, your body is asked to work harder. But have no fear! Once you get your feet (and the rest of you) wet, you’ll build endurance fast and quickly learn to love this soothing, no-impact workout that burns more than 500 calories an hour.

Breathe.
It’s the single most important thing to master in swimming. A steady inhale/exhale rhythm keeps you relaxed (like in yoga) while increasing your speed and eliminating the need to gasp for air every couple of strokes. Breathe out of your nose while your face is in the water and, on every other stroke, tilt your head to the side, halfway out of the water, and take in oxygen. Once you’re comfortable with that, breathe in on every third stroke to practice getting air on both sides, a handy skill in open water since waves may break on your favored side.

Roll with it.
Rotate your shoulders, torso, and hips with each stroke to help you glide through the water. If you rotate your body from side to side—rather than swimming flat, you’ll move like a torpedo.

Kick sparingly.
Save your legs for the bike and run, and rely mostly on your arms to pull you through the water. This prevents lactic acid from building up in your legs, which in turn keeps your legs from tiring so they’re ready when you really need them. During training, squeeze a pool buoy between your legs as you swim to practice using your upper body.

Do It!
At first, aim to swim 250 meters once or twice a week. If you’re sucking wind (or water), break it into intervals of 25 meters (usually one length of a pool) of nonstop swimming with 20 seconds of rest in between to catch your breath. During the final month, make one session each week an open-water swim, if possible, and practice sighting by looking up every six to eight strokes to confirm you’re on course. Start each workout with 10 to 15 minutes of the following warmup drills. These three exercises will refine your stroke and help you generate more power so you can learn to glide through the water effortlessly.

Catch-up Drill (for stroke timing): Swim freestyle as usual, but leave one hand in front until your other hand finishes the stroke and comes around to “tag” it.

Side-Swim Drill (for body position): Hold your left hand in front of you, palm down. Swim with your left side, eyes looking at the bottom of the pool and right hand glued to your right thigh for six kicks. Stroke with your left hand, rotate, and switch sides. Repeat.

Fingertip Drag (for arm position): As each hand ends its stroke, keep your elbow high and carefully drag your fingertips along the surface as you bring your arm forward.

Biking

Triathletes consider the relatively “easy” cycling leg child’s play, after all, most people learned to ride when they were missing their two front teeth. And while the skill of bike riding does come right back, there are a few training tricks that will help you build lean muscle and pump the pedals on race day. With proper prep, those 12 miles will fly by faster than you think.

Technique 101

Spin your wheels.

Your bike is powered by your legs and core, which means your upper body should be relaxed and motionless as your lower half does the work. Try not to hold tension up top.

Shift.
Most beginners fall in love with one gear and don’t shift as often as they should. You want less resistance while going uphill, so shift down into a lower gear (your legs will spin faster and with less effort) to help you over a climb. Do the same whenever you come to a complete stop, starting again will feel 10 times easier in a low gear. On flat or downhill terrain, shift up to a harder gear to add resistance so you’re not just coasting but powering through.

Pedal evenly.
A good pedal stroke should be about pulling as much as pushing, a complete circle of power and efficiency. And the smoothness will help your entire form. If you have a perfectly round pedal stroke, you’ll notice your hips, shoulders, and torso are stationary.

Do It!
If the last bike you rode was pink and had a basket on the front, start by taking a spin class or riding a stationary bike at your gym for 30 minutes. Do that two or three times a week to remind your muscles how to pedal before hitting the road. Once you’re used to the gym bike, hop on a road bike twice a week for 30 minutes (to start). Just don’t forget to vary your terrain, especially if you’re prepping for a hilly racecourse.

Running

Because running is the last leg of the race, your training goal is to build muscle endurance so you’ll be able to finish strong when you’re spent from swimming and biking. Since you have to bang out only a few miles on race day, your running training focuses on boosting your body’s VO2 max, or its efficiency in using oxygen, to get you through all three legs. And the best way to do that is by running shorter distances at higher intensities. In other words, intervals.

Technique 101

Shorten your stride.
Reducing your stride lessens the impact on your body, which cuts your injury risk and also keeps your feet happy because they’re spending less time on the ground. Count the number of steps you take per minute and aim for 180 (or three steps per second) as your goal.

Run relaxed.
Bend your elbows to form 90-degree angles and make sure your fists aren’t clenched. Keep your jaw loose and your shoulders down. During easy runs, you should be able to carry on a conversation. If you can’t, slow down.

Do It!
Start the first month with 20-minute runs twice a week, increasing time or distance by no more than 10 percent each week. Smacks of slacking off? You’re really not: Thanks to your bike and swim cardio, 20 minutes is all you need right now to stay fit. Adding two-minute speed intervals will strengthen your legs and build the power you’ll need to finish strong on race day. Before you dash, warm up your running muscles with the three plyometrics moves below. Do each one for 10 to 15 steps, rest for 30 seconds, and repeat once.

Walking Lunges: Step forward with your right foot and lower your body until both knees are bent 90 degrees, keeping your right knee behind your toes. Push off your front foot and switch legs, moving forward.

Butt Kicks: Run forward, kicking your feet directly behind your body so that your heels touch your butt.

Bounding: Run with an exaggerated stride length, lifting your front knee high with each bound.

www.womenshealthmag.com/fitness/triathlon-women