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Meet The Team


Mariah Nieto


  • Mama of 2 little and Wife

  • CrossFit Level 1 Trainer

  • 20 Time World Champion Martial Artist

  • 4th Degree Master Instructor (Arnis Sikaran Jornales System, FMA)

  • Motivational Speaker

  • MPA

  • Alto/Lowell Native

  • Lover of all things fitness and  outdoors

Hello! I am Mariah. I always joke that I am just a small town girl with big dreams and the drive to make those dreams a reality - but its true! As a little girl, I remember having 3 main goals/dreams (my parents always told me its was important to set goals for yourself).

  1.  I wanted to be a black belt - DONE! (I actually have 3 black belts - Arnis, Karate, and TaeKwonDo).

  2. I wanted to become a World Champion in Martial Arts - DONE! I earned my very first titles when I was 12, and retired (temporarily) with 20!

  3. Own my own gym - DONE!

In a VERY long story short, I found CrossFit when I retired from competing in Martial Arts. From my very first class, I was HOOKED! I loved the atmosphere, community, workouts, and everything in between! When I found AVCF, about 3 years into my CF journey, I knew I was home. I was welcomed in like an old family friend, and had the time of my life training! A year later Mitch and Kyle asked me to be a coach for them, and I obviously said YES! In late 2021, they then asked me if I would be interested in buying the business. That was the easiest answer - OF COURSE! They knew that I would take what they had worked so hard to create, and continue their legacy and grow the gym. It is important to me to not only provide an exceptional level of training and fitness, but to make every single person who walks through our doors feel welcome and "home" like I did. I want EVERYONE to feel comfortable in our gym - whether on day one of their fitness journey or an experienced athlete. We welcome EVERYONE! We have fostered a community of people and a  culture that is second to none - and that is SO important. That, coupled with amazing programming and coaching, AVCF is a fitness destination for ALL. 


Kyle Krebill

Founder, Coach

Born and Raised in  Grand Rapids/Lowell

• Dedicated Husband & Father

• CMU Alumni

• CrossFit Level 1 Trainer

I found CrossFit in early 2015 when my sister encouraged me to attend a class with her. I started to fall out of my active lifestyle and am not afraid to embrace a good challenge… additionally, I was done using the excuse of having no energy and being overweight as just a condition of getting older. What I found after the first class (although I was nervous and intimidated) was the most life changing experience I could have ever imagined! The classes were fun, the community was encouraging, and the transformation, both mentally and physically, has been life changing. The more classes I attended, the more I got out of it. And it never gets old as it’s something new and more challenging every day. With seeing the CrossFit methodology work so brilliantly, I couldn’t wait to open Ada Valley CrossFit (along with the help of some great friends and family) in this community that I live in. I hope to share the fun, the healthy lifestyle and the comradery with all of you soon.

Mitch Bio Pic.jpeg

Mitch Lukaart

Founder, Coach

• Born and Raised in

Grand Rapids/Jenison

• Husband and Father of two

• CMU Alumni

• CrossFit Level 1 Trainer


I discovered CrossFit in 2015.  My friend had been inviting me for a good 7 months before I finally gave it a try.  I had all of the excuses not to try it like "That isn't for me", "It's too hard", and "I'm not in good enough shape to do that."  Wow, was I wrong.! I  instantly fell in love.  I found that all I had to do was show up and work hard, and it wasn't long before I was doing things I never thought I could do.  It wasn't about me compared to everyone else.  It was about my own progress.   I really enjoyed the community and also the sense of accomplishment I felt after finishing the workout.   I found myself enjoying the competition and camaraderie that I had been missing since high school sports.   I wish I would have tried it sooner." 


Jacqueline Poulson


  • Arizona native

  • Northern Michigan University Alumni

  • Mom to Conrad (2) and fur-babies Portia (Terrier-Mix) and Blondie (German Shepard)


I found Crossfit in early 2014. What started as a way for me to “get in shape” for my wedding, quickly turned into a torrid love affair. I thought I would only be at the box for a couple of months, but I enjoyed the community and constantly varied movements so much, that I made my husband, Ryan, and all our friends join too! I enjoy how Crossfit always presents a new challenge, regardless of experience level. And while the physical transformation is nice to watch, I am more amazed at the mental toughness Crossfit creates. The people and community of Ada Valley Crossfit have always been my favorite aspect since we joined in 2018. I love double-unders and strangely enough, burpees, and have a strong disdain for anything that highlights my shortness, like wall-balls or rowing! I look forward to helping others reach their goals.

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Alex Sackett


• Husband and Father of two

• Geologist

• Crossfit Level 1 Trainer

 My athletic background started just 12 miles south of Ada Valley CrossFit. Born and raised in the small town of Caledonia, outside of Grand Rapids, I played Football and Lacrosse for the varsity programs.  Though I thought of myself as “fit” growing up, it wasn’t till February of 2015 I would humbly find out what being “fit” meant.  With over 2 years of CrossFit experience under my belt, I continue to work towards being the best version of myself; physically, mentally and emotionally.  CrossFit is so much more than just “Constantly Varied, Functional Movements, at High Intensity” and Ada Valley is so much more than just a Box.  With the CrossFit methodology backed by such a supportive and positive community you have a recipe for a life changing journey.  It’s a journey that all of us at Ada Valley CrossFit are on and we are loving every step!

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