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FIT Thornton delivers the CrossFit program exactly as it is intended. The stimulus provided are by design, constantly varied, using functional movements, performed at a high intensity. Our specialty is not specializing and our goal is constant progress. The community is welcoming, and is one of support and camaraderie to anyone seeking maximal health and fitness. Whether you are an ELITE athlete, actively participating in sports, playing with your kids, or simply wanting to be healthier and more mobile, we strive to provide the highest level of training that will help you achieve your goals.



"I love the atmosphere of CrossFit Thornton. The friendly vibe and supportiveness of all the members keep me coming back. That and the coaching – I’ve never had this kind of attention to detail without having to pay for a personal trainer!"

− Sarah

"I’ve been a member at this gym for about 3 weeks. When I walked in the door for the first time I didn’t know how to do any of the lifts. The coaches are very knowledgable and eager to help. They go over every single exercise that we will need to know for the warmup and for the actual workout. They are very attentive. They are constantly coaching, giving motivation and tips on technique during the workouts. I’m not an athlete and I’m also a little shy. When I went to my first workout the other members introduced themselves to me right away. It made me feel very comfortable. Everyone supports each other during the workout. Members want to see each other do well. It’s a great gym."

− Lexington

"My experience at CrossFit Thornton has been and will continue to be life changing. Our coaches have created an environment that is inviting to everyone not to mention the knowledge and expertise they bring to our box. So many people ask me if CrossFit is easy and if they can do it. The truth is, it never gets easy. You just get better. CrossFit is perfectly designed to push you as far as you are able to go no matter what level you are. You will not find a better community of athletes & coaches anywhere else."

− Kristi

"After a number of years of inactivity and general health decline, I was looking for a place to build my overall fitness, challenge myself mentally, learn new things and make some new friends. Amen! I found it all at CrossFit Thornton. Great coaches. Great community. I feel more confident in my workouts and I now have a sustainable way to maintain better health and longevity. Thank you CrossFit Thornton."

− JIm

Try us Free for 1 Week, only $59 for CrossFit & More in Thornton, CO

More Choices in Thornton

We are the Best Gym in Thornton for High Intensity Workouts. You can choose between CrossFit and FIT Boot Camp at one location. We are the only gym around Thornton to give you so many choices. What is your goal? Are you looking to get stronger, lose weight, get in shape, or just get healthy again? The answer to your fitness goal is the same. Find a High Intensity Training program at a Gym you will enjoy and can attend 3 to 5 times per week.

FIT Thornton CrossFit is open 7 days per week. Our Health Club serves people who live and work around Thornton and Northglenn. Our Gym offers over 100 class times on the schedule. You won’t find more flexibility to get your workout in than at our Fitness Facility anywhere in Colorado. We have CrossFit workouts 7 days per week and FIT Boot Camp workouts 7 days per week. Our first class starts at 5am and our last class finishes at 7:30pm. We have the High Intensity Training Program you’re looking for.

Do you want to do Cardio today? Come join us for a FIT Boot Camp Fitness class in Thornton. Are you looking to get stronger today? Join a CrossFit workout near Thornton and improve your strength. Our Gym has a class on the schedule for you, no matter how busy you are. Try us out FREE for 1 week and see why we have become the best gym and fastest growing fitness facility around.

World Class Coaches near Northglenn

A gym is only as good as its coaches. At our Health Club in Thornton near Northglenn, we are lucky to have some of Colorado’s best fitness coaches calling FIT Thornton home. Join us for a workout with a coach who cares about YOUR success.

Our coaches in Thornton are highly educated specialists in Weight Loss, Nutrition, Thornton CrossFit, Olympic Lifting, Boot Camp, Running, Cycling & more. From the first time you arrive in our gym, you will notice our level of dedication. We provide the right amount of motivation and experience, without being “too close for comfort”. With our varied backgrounds and specialties, you will find an experience unparalleled in our area. Try us FREE for 1 week. We have over 30 positive reviews so far, making us Thornton’s #1 gym for High Intensity Training workouts. Come see the difference our dedicated coaches near Northglenn create.

*Our programs were brought together by Nathan Lemon. In addition to losing over 100 lbs himself, he has won multiple amateur boxing titles, ran in numerous half marathons, and loves obstacle course races. His program creates a unique twist on Boot Camp by combining all the elements you love in a Boot Camp class with all the toys available at our  CrossFit Gym in Thornton. By creating a program that burns over 900 calories per hour, Nathan has become one of the best trainers in Thornton and Northglenn.

Perfect Location

FIT Thornton is located just off I-25 and 120th Avenue in Thornton Colorado.  Head East off of Interstate 25 two blocks to Pennsylvania Avenue and go North.  We are easily located by our red directional signs that point to our newly expanded 5,000 square foot facility near Northglenn and Welby.

Low Coach to Athlete ratio

Our Thornton CrossFit Gym Workouts were built to get you individualized coaching in a group atmosphere. We believe in this philosophy and average 1 coach for every 7 members in a class so that you always get the attention you deserve. We are the only  CrossFit gym serving Thornton and Northglenn to give this low coach to athlete ratio. You will always get better results when your coach has the time to focus on you.

Incredible Facility

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History of CrossFit

CrossFit was formally established in 2000 by Greg Glassman. By 2005 there were 13 affiliate gyms. Because of the incredible results people have seen, there are now over 8,800 CrossFit affiliate gyms worldwide, making it the largest fitness organization in the world. How do you argue with those results? One of the best articles, published by “The Box” magazine, outlines the history of CrossFit. One of CrossFit’s largest strengths is that it is scalable and usable by anyone at any age. There are 80 year old people using CrossFit to stay healthy, 350lb + people using CrossFit to lose weight, and 5 year old children using it to learn about fitness. Even the US Military uses the methodology to train it’s Special Forces.

A simple way to sum it up. CrossFit founder Greg Glassman realized that specializing in one athletic domain meant losing the ability of the athlete to perform in others. Think of the strength capacity of a marathon runner, or the endurance capacity of a power lifter? They gave up one capacity for another. Greg’s goal was to determine the “Best methodology to determine and produce the fittest humans on the plant”. His discovery was that by mixing the best training disciplines of other sports, we could become the best and most fit versions of ourselves. What is athleticism? It is being able to perform optimally in the following modal domains: cardiovascular/respiratory endurance, stamina, strength, flexibility, power, speed, coordination, agility, balance and accuracy.

CrossFit is the most effective way to do this, in the least amount of time. 8,800 gyms and hundreds of thousands of people can’t be wrong. If you’re in or near Thornton or Northglenn and surrounding areas, come join a CrossFit Gym who values you as an individual and wants to help you achieve your goals.