The center is an official CrossFit® affiliate. Last checked: 13/08/2025

CrossFit is a registered trademark owned by CrossFit, LLC, which is not affiliated with FitFit United States.

Information about CrossFit® Nucleus

Old Fullerton Rd 350
62226, Belleville
+1 618-416-8677

Opening hours

  • Monday: 6:00 AM – 8:00 PM
  • Tuesday: 6:00 AM – 8:00 PM
  • Wednesday: 6:00 AM – 8:00 PM
  • Thursday: 6:00 AM – 8:00 PM
  • Friday: 6:00 AM – 8:00 PM
  • Saturday: 9:00 – 11:00 AM
  • Sunday: Closed

Services, Machines and Guided Classes

CrossFit®

CrossFit® Nucleus: Opinions

4.8/5 (17 Opinions)
Emily 1 year ago

Fantastic experience: Wonderful gym w specialized training

Anthony Duran 2 years ago

Fantastic experience: Great coaches, great atmosphere, great people.

Brandy Stone 4 years ago

Fantastic experience: People were welcoming. Clean

Dr. Benjamin Brown 4 years ago

Fantastic experience: If you are looking to improve your fitness, this is the place for you. Great facility, great coaching, and great equipment with a great community of support!

Joshua Tapley 5 years ago

Fantastic experience: Best gym and best people! I love this place!

Joseph Moreland 5 years ago

Fantastic experience: Great coaches, great facility.

Mspei80 6 years ago

Fantastic experience: I began training with Mike Whetstone and his family / staff when I was in High School. The amount of knowledge that I have learned from this great group of people is astounding. 5 years later I am still using the skills they have taught me. Not only did I expand my physical strengths and limitations, my entire fitness mentality and nutritional mindset changed. This gym offers an absolute great experience for those who are both new and prestigious when it comes to physical fitness. No matter who you are or what you can do, you will learn the very best information from the very best coaches. The classes are fun, enjoyable, and can have amazing results. The high tempo vibes are constantly given off from the coaches, and they are always there next to you ensuring you're doing everything correctly and efficiently. They will push you to your limits, while maintaining a safe workout environment. Mike and all of CrossFit Nucleus helped me prepare myself and my body before joining the United States Marine Corps, and I can not be thankful enough. They gave me the physical and mental tools I needed to help better myself on a daily basis, and I look to all of them as family. Whether my form is off, or I have a personal problem at home, these people play a big role in my life. I challenge you to give this gym a try, it can change your life!

Jacquilin DeWolf 6 years ago

Fantastic experience: Great staff! Beautiful facility! The yoga instructor, Meredith, was very thorough with her directions and helpful in correcting the poses. The sauna was perfect and, the locker rooms were immaculate. They even have a child care area!

Paulette Green 6 years ago

Fantastic experience: Cannot speak to the workout room or trainers. But Meridith the massage therapist is AMAZING

Sean Gilson 6 years ago

Fantastic experience: In the area for mil training; dropped in for a week at CF Nucleus and couldn’t have been happier with the hospitality of the members, attention to detail by the coaches, and cleanliness/amenities of the gym. Thanks for reppin’ CF well guys. Keep up the good work!

Richard Kapp 7 years ago

Fantastic experience: I have been a member since May 2014 and it has been an amazing journey! The coaches are incredible and know how to help both those new to crossfit and seasoned veterans. Classes are fun, but challenging and everyone encourages and motivates one another. You'll push your mind and body to new limits that you didnt know were possible! Drop in for a visit and I know you won't be disappointed.

Lauren Ashton 7 years ago

Fantastic experience: Plenty of equipment, plenty of space, very clean. They also have a sauna. Bet you won't find that at any other CF gym in the area. The 1 coach Lindsey is very hot, hot, hot.

Erik Schlosser 7 years ago

Fantastic experience: The trainers are all excellent and very knowledgeable. They make sure you’re movements are correct and watch closely at form. Anyone who is new to crossfit will have no problem transitioning into the sport with the trainers help! The people who attend were very welcoming. The equipment is clean and well kept. Overall, I’d highly recommend Crossfit Nucleus! It is where I started crossfit as a complete beginner, and through Crossfit Nucleus I have become stronger both mentally and physically!

Melissa Gaa 7 years ago

Fantastic experience: Awesome gym, amazing large facility and the great coaches. Would highly recommend joining. The programming is phenomenal for any level of fitness and any age including children classes. They have two massage therapists, yoga teachers and a chiropractor which are amazing!!! This comes from a member who has been attending for 4 years.

Heather Marshall 8 years ago

Fantastic experience: I highly recommend anyone wanting to get in shape to join this gym. I love the programming, you do something different everyday. The coaches are motivating and supportive. They have all the equipment you need along with a great group of people to workout with. They also have a kiddie area for your kids to play while you get a workout in!

Lifestyles of the Holloman's 8 years ago

Fantastic experience: Went for a massage. I thought they were very professional. She also offers military discounts on her services.

Chase Lodes 9 years ago

Negative experience: I don't want to degrade this gym when it comes to cleanliness or equipment. But, I will however, complain about how unprofessional and rude the employees and owners are. They enjoy starting petty arguments on non-aggressive Facebook posts and treat me poorly because of my age. They were very condescending toward my personal views and frequently disregard the fact that I am a paying customer. They will not receive anymore business from me or any of my family.

Leave your opinion about CrossFit® Nucleus:

1 = Poor 5 = Excellent

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