(If you're just starting, you could look up to Gwen Jorgensen, celebrating her win of the Elite Women 2015 ITU World Triathlon Grand Final Chicago here.Kamil Krzaczynski-USA TODAY Sports)

Spring is in the air — even if it isn't technically here yet. During the winter, many of us spend too much time huddled indoors, being more sedentary than is healthy.

That's not great for our bodies or our minds, which is why so many people jump on new 'get in shape' routines as soon as nice weather hits.

Those really looking to get into shape should set a goal, something that will keep you working out regularly and force you to put a training routine on your calendar.

If you're feeling ambitious, the ideal competition may be a triathlon. The combination of running, biking, and swimming forces you to mix up your workouts, training the whole body, which will get you in great shape and could make you less vulnerable to an overuse injury.

The sport of triathlon is having a moment, says Dan Arnett, a professional coach who has competed in world championship races and Ironmans (which include a 2.4 mile swim, 112 mile bike ride, and a marathon to top things off). Participation in triathlon events has skyrocketed in recent years, and now sits at near-record levels.

Business Insider spoke with Arnett about his recommendations for beginners.

Find a race

Triathlons come in varied distances — there are very short ones and ultra-length races like the Ironman. Start with a sprint distance, Arnett says, since "that very first competition should be about you finishing."

A sprint tri consists of a 750 meter swim, a 20 kilometer bike ride, and a 5 kilometer run — distances that are within reach for anyone in reasonable shape, with a bit of training. Arnett says to give yourself at least eight weeks, though the more time you have, the better.

Pick a training plan — and stick to it

"You do not need a coach," says this professional coach who gets paid to work with triathletes. "What you need is a plan."

There are plenty of free plans online that will tell you everything you need to know, he says. Some are available on sites like BeginnerTriathlete, and there's also free software on sites like TrainingPeaks. You should schedule workouts in your calendar as if they're meetings you can't skip — otherwise it's too easy to procrastinate.

(Flickr/Nathan Rupert)

Luckily, injury rates aren't particularly high for triathletes. Since the training requires you to strengthen different parts of your body, overuse injuries are far less common than they are for single-discipline athletes. Still, don't forget to let your body rest.