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The Earth is Your Gym

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Joe & Nicole Decker

Gut Check Fitness was founded in 2006 in San Diego by Joe Decker and his wife, Nicole. They started an affiliate program in 2013, fulfilling their dream of bringing their one-of-a-kind outdoor fitness company to cities around the world. Joe Decker is recognized as “The Worlds Fittest Man,” an ultra-endurance power athlete, renowned fitness trainer, and syndicated columnist who has helped thousands of women, men, kids and seniors get into shape and lose weight.

This outdoor workout format that Joe created is the same that he used to break the Guinness World Records® 24-Hour Physical Fitness Challenge in 2000. It works like no other program out there, getting people into the best shape of their lives. Joe believes in leading by example and is a personal testament to overcoming addictions and obstacles. Once overweight and out of shape, Joe transformed his body and his life through an amazing journey from fat to fittest.

Joe has appeared on The Today Show, Discovery Health, The Early Show, The O’Reilly Factor, and Fox News and has been featured in The Washington Post, The Philadelphia Inquirer, The Baltimore Sun, Men’s Fitness, Muscle and Fitness, Men’s Health, and GQ. To his surprise, People Magazine named him one of America’s 50 Most Eligible Bachelors in 2001. In addition to breaking the world fitness record, Joe has competed in many of the world’s toughest endurance and adventure fitness events. Some of these include the Raid Gauloises, the Badwater 135, the Marathon des Sables (“The World’s Toughest Footrace”), the Grandslam of UltraRunning, and The Tough Guy Challenge in England.

After serving 3 years in the Army with the 10th Mountain Division, Joe graduated from Western Illinois University with a B.S. degree in Exercise Science. He founded his own high-speed fitness company working with individuals, groups, and corporate clients. Joe is regularly involved in charity work and has established a research foundation for childhood obesity from his winnings on The Weakest Link. He lives and works in the San Diego area.

Joe Decker has been competing in Powerlifting for 23 years, Strongman Competitions for 10 years, and Ultra Running for about 10 years too. The daily and weekly workouts that he utilizes are a combination of his years of Extreme Competition experience, high-speed military background, top-notch college education, and rugged Midwestern farm upbringing.


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wE ARE the Premier outdoor fitness and Event program

Escape the monotony of treadmills and overcrowded gyms and relish the exhilaration of running along scenic trails and engaging in invigorating workouts on the beach, surrounded by the beauty of the great outdoors. Our fitness program boasts a world-class team of instructors who specialize in delivering high-energy boot camp-style workouts, fueled by positive reinforcement. Embrace the opportunity to join a vibrant social network of like-minded individuals who share a passion for pushing their limits and achieving their full potential.



"Gut Check is an empowering addiction. They take advantage of San Diego's beauty and bring together a community of some kick ass people".

Maecie K.

"Gut Check Fitness got me out of my comfort zone and into the best shape of my life".

Kevin C.

 "I lost weight, gained strength and endurance and had fun doing it". 

David K.


Gut check Fitness

We are the premier outdoor fitness and event company. Ditch the treadmills and the crowded gyms. Enjoy running the trails and working out at the beach in the great outdoors.


We have a world-class team of instructors, offering high-energy boot camp style workouts and positive reinforcement. Burn up to 1,000 calories during a class, build muscle, maximize fat loss, and increase your metabolism. 

Join our social network of like-minded individuals that love pushing themselves to the limit.

Are you training for a Spartan Race, or perhaps a Tough Mudder, maybe a Ragnar, or an ultra-marathon?  You've found the right outdoor fitness program. "Why settle for the good when you can go for the great."


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