More than a million non-professional athletes compete in triathlons in the US every year, an increase of more than 40 percent in less than a decade. And according to statistics, released by USA Triathlon, close to 40 percent of them are women. But for beginners, training can be an enormous challenge. You’re going to be swimming a half-mile; cycling 12 miles; and running 3.1 miles; but it isn’t enough to simply swim, cycle and run to get fit. Instead, you need a well-constructed training plan that will build your level of fitness steadily, week by week. Alison Kreideweis, a co-founder of New York’s Empire Triathlon Club, advocates a 12-week course to boost confidence and learn what new triathlon competitors need to know to train effectively for their first race.

What’s more, training should be “purposeful, productive and enjoyable” according to USA Triathlon. Each training session should have a specific purpose. For instance, to help you run faster, develop your body power, or build up your overall endurance—link all training elements to long-term and short-term goals. If you get this part right, you’ll be productive and enjoy your training all the more.

There are several key rules when it comes to successful triathlon training. These include running at least twice a week; practicing a weekly endurance workout; doing a long run once a week; and working on treadmills for steady rate-run and interval training. Practicing stacks on a regular basis, by running as soon as you get off your bike, is also very effective. One of the most important “rules” to stick to is the 10 percent rule for increasing the distance that you run, cycle or swim. Athletes who don’t stick to the 10% rule have a good chance of injury, particularly during run training. Kreideweis suggests slowly building up the intensity of training, which should be at its most intense in the middle of your training plan, and should wind down shortly before the race. This way “your body will be rested and ready,” she says.

Need some help getting started? Find free training plans on the Internet, or join a club or fitness center where qualified help is available – and where you can meet other people with similar goals.

Of course proper health and nutrition are also vital for all athletes, and it is extremely important to drink enough water. Athletic nutrition coach, Kim Mueller, herself a triathlete, maintains that “slacking on water” is a common mistake athletes make. Loss of fluids is a sure way to decrease performance, she warns. She advises triathletes in training to start hoarding both glycogen (stored energy that is converted from common carbohydrates like pasta) and water, long before race day. Throughout your training, she says, drink eight to twelve cups of water each day, depending how active you are.