Mission Statement

At Supreme Strength we provide top of the line powerlifting coaching for the driven athlete. With a combined 20+ years of experience in high-level powerlifting coaching and competing, we have the confidence and the know-how to coach you to new heights. Our coaching is about finetuning an approach and figuring out what really works for you, letting go of any biases we have.

Meet the Coaches

Coen de Heer

I have been coaching powerlifters for 6 years now and have been competing in powerlifting for 8 years. I naturally moved into coaching powerlifters as a result of wanting to test theories and concepts I learned and read about as I was diving into strength and conditioning research.
What started off as coaching some friends and training partners has turned into my life's work. Coaching powerlifters on every level, owning a powerlifting gym and actively pursuing powerlifting myself. You could say that I like powerlifting… a lot.

Planning out training and making adjustments or testing concepts based on athlete feedback and novel research has made powerlifting coaching into a never puzzle for me and the people I work with.
Designing a training plan can be done in an almost infinite set of ways. Doing things that work and adding some exploratory strategies keeps training interesting and fun!

A lifter's excitement after a successful training cycle is what keeps my drive high!
Finding the current needs while building long term success is our key to succes.
The what and how that emerges from this goal is dependent on the individual.
Having a broad scope of athletes keeps me on my toes, looking for new strategies and developing as a coach and person to help you on your way.


Rijker Cox

What first started as an interest in Natural Bodybuilding became a never-ending pursuit for strength. Drawing inspiration from the likes of Layne Norton and Eric Helms early on, I became more and more captivated by the principles of hypertrophy and programming for strength. What made their work so appealing to me is how they combined science backed methods with hard gritty training. During my time powerlifting I developed a a true passion for coaching and guiding people towards their strength and physique goals. This led me to coaching multiple athletes towards international  championships and many medals along the way. 


With a background in Sports and Performance Psychology I can offer my athletes the mental edge when it comes to training and competing. When I work with athletes I like to make long term plans together and aim to make them aware of all the boxes that need to be checked to achieve their version of success. Having dealt with injury for a good part of my own powerlifting endeavours, I have become more resourceful and creative as a coach. I am always open to new concepts and ideas and am willing to dive into uncharted territory with my lifters.


Sil Maris

When I moved to Groningen to study, I didn’t want to play football anymore and started going to the gym. The gym in question was powerlifting association Northside Barbell, where I immediately came into contact with the sport of powerlifting. Although I joined a gym because I mainly wanted to look a little more muscular, it quickly sucked me into the never-ending quest to become as strong as possible. I started to research as much as I could about the principles of muscle growth, powerlifting technique and programming to try to optimise my training. In the years that followed, I developed myself as a lifter and became strong enough to end up on the Dutch team and I participated in the European & World Championships.


In the last 4 years I have begun coaching powerlifters. Helping different types of lifters on different levels has made me grow as a coach. Providing punctual, data-based programming is my strong suite and what distinguishes me as a coach. Furthermore, good coaching stands or falls with communication if you ask me. I make sure to communicate a lot with my lifter and I also expect clear communication on all facets of his or her training, so that we can come to the most optimal training together. Also, because I am naturally very curious and have a drive to always be the best I can be, I will never stop developing myself as a lifter and coach.