We don’t often think about our skeletons. But if you recently had a come-to-Jesus moment with yours — a time when it seemed like someone had removed it from your body and clubbed it with a bat — you may have run a marathon.

“I am way more sore after a marathon than an Ironman!” says Eddie Morin, a runner and triathlete who recently raced the Austin Marathon. “Usually after a marathon, I can barely walk. As soon as I cross the finish line, I immediately become an ‘old man.’ But after an Ironman, I can jog the next day.”

And keep in mind that Morin is an elite athlete sponsored by Michelob Ultra. And that an Ironman means swimming 2.4 miles, biking 114, and then running 26.2.

Even some more casual athletes who’ve tried both types of races say they feel better after the triathlon, even if it takes hours longer. Austin physical therapist Becky Wooster has done both half-marathons and sprint triathlons, but found the triathlons easier on her body. “And my professional opinion agrees with the anecdotal evidence,” she says with a smile.

If you’re among the countless American distance runners looking for a new fitness challenge that shreds as many calories without as much pounding, it may be time to try a triathlon.

Triathlon is amping up as a sport, with nearly 2.3 million people competing in the U.S. in 2011. That's up from just 1.5 million in 2009. Tri's inclusion as an Olympic event in 2000 revved up public interest, and it’s been racing ahead ever since.

Mike Thompson of Jack & Adam’s Bicycles got into triathlon for the challenging physical variety — and the social side. “All you have to do is try it,” he says. “It’s a super-positive and uplifting community to be a part of.”

And no one needed such a community more than Thompson. A childhood leukemia survivor, he found out he had a tumor in his jaw in 2000, and doctors used part of his fibula to reconstruct after surgery.

They said he wouldn’t be able to run well again, let alone do triathlons. But today he’s even done the world’s most sought-after Ironman, the Kona World Championship in Hawaii. Thompson says triathlon gave him passion in life once again.

The Texas tri community is big. As it happens, Texas by far the highest number of USA Triathlon members of any state in the country, with around 18,000 — dramatically higher than even California. (And psh, they think they're so hyper-fit!)

Austin in particular has fun, approachable races; good sources for equipment and expertise; and an exciting environment for training.

Here are some tips on getting started:

Distances: You definitely don’t need to start with an Ironman. There are Half-Ironman races, which are 50 percent of the full distances. But super-sprint races generally start with only a quarter-mile swim, 10k bike, and 1.5-mile run. Sprint races involve a 750-meter swim, 20k bike, and 5k run. And Olympic tris take a 1.5-mile swim, 40k bike, and 10k run.

Races: The Rookie Tri, being held this year on May 5, is a great starter race that’s close to super-sprint distance, Thompson says. The Danskin is always a popular option for women at a sprint distance in June. Another sprint, the Couples Tri in July, is a great way to share the fun with a partner, relative or friend. The Austin TriRock provides the rare chance to do a triathlon at an Olympic (or sprint) distance downtown at Labor Day. And the list goes on.

Planning to Train: It’s the perfect time to be getting ready for the season, with eight-12 weeks prep ideal. Many Texas races start late spring and continue through fall. You can do much swimming in a pool, which is convenient in triple-digit temps when you still want a workout. Just plan to do multiple open-water swims as well. Beginnertriathlete.com and trinewbie.com offer free training plans.

Finding Community: The 400-member Texas Tri Series Facebook group posts tons of training events. Jack & Adam’s, which takes a local lead in promoting triathlons, sponsors a Sunday-morning ride, a Tuesday evening group run, and more free events weekly that Thompson naturally recommends. Rogue Training Systems offers group training for specific events, including an “Iron Chicks” crew that prepares for the Danskin.

Training Grounds: Lake Pflugerville, the Loop 360 bridge area, the Pure Austin Quarry Lake, and Walter E. Long Metropolitan Park (a.k.a. Decker Lake) are popular area places for triathlon practice. All offer safe open-water swimming and biking environments that range from flat around Pflugerville to steep on 360. You’ll find fellow triathletes training, especially early on weekends.

Transitioning: Don’t be intimidated of the “transition” between the different triathlon segments — they just take practice. The Splash-n-Dash series of short Tuesday night swims-plus-runs provides a great chance for that. They’re held monthly all summer.

Basic equipment: There’s the perception that triathlon can be expensive. And yes, compared to running, which needs little more than shoes, it can take a bit more. But there are ways to keep costs down.

If you own a bike and a swimsuit, use them to start. If you like the sport, you can upgrade to fancier gear later. Or if you think you want to give triathlon a serious go, Jack & Adam’s typically offers a Beginner’s Package for just under $1,000 that includes a bike, helmet and every smaller item you could possibly need.

Other costs: Because they are complex and require insurance, triathlon entry fees aren’t cheap. Then again, neither are road races these days. Expect tri registry to cost around 30 percent more than running-only events.

You’re likely to pick up on all these tips and more during training with fellow triathletes. You could keep pounding away on long solo runs in training for marathons, but veterans of both like Morin, Wooster, and Thompson ask: Why? “The training is more fun and social and dynamic in how you treat your body,” Thompson says. “It creates a more well-rounded athlete. And in my opinion, it’s just fun.”