Sterck logo tranp
Gym owners

Do you want more gym members?

Growing your gym can be difficult. We make it easy. We help fitness entrepreneurs with more members, more turnover, and less customer churn, completely on autopilot.

Our method

We generate leads in 4 steps.

01. More leads

We create a greater reach and consistently generate new leads

02. More appointments

We provide support in converting leads into concrete agreements

03. Increase conversion

We contribute to a greater conversion from appointment to paying member

04. Higher customer value

We increase the value of members, resulting in higher turnover for every member

Tim van Son

Find out within 15 minutes what we can do for you!

Ready to grow your gym? Contact us for a free introduction!

Who we are

Why we are your ideal partner

Since 2013, we have been helping people achieve a fit lifestyle online with – the largest online fitness platform in the Netherlands and Belgium. With a monthly reach of more than 200,000 visitors, has helped a total of more than 30,000 people take a step towards a healthy lifestyle. That’s not all, in two years we have grown the number of paying members from 250 to more than 2,000 members.

We wanted to do this trick more often – and that is where Sterck was born. Based on our years of experience in the fitness industry, we help fitness entrepreneurs like you achieve consistent membership growth, more turnover and a more stable business.

New members
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Happy customers

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The Sterck team has given a significant boost in terms of branding and conversion. Thanks to the expertise of Wiebren and Tim, we have improved our conversion by more than 50% and with a professional appearance.




We are very satisfied with all the work that Tim van Sterck does for us. We can always help you with questions about the world of marketing and media. With Sterck’s help, we are well on our way to realizing our vision! Together with the Sterck team and our enthusiasm, we have a right to exist here!


Owner zerofifty Sports & fights


We were looking for a loyal online marketing agency for our outdoor location. After a lesser experience elsewhere, I ended up at Wiebren and Tim van Sterck and super happy with it!

Our niche (outdoor strength training) is quite a difficult one when it comes to collecting leads, but due to fast action and good communication, we have already had quite a few people come for a trial lesson (with success!).


Owner KR8IG outdoor sports

Together we are STRONG

Jouw vragen Beantwoord

Hier een aantal van de meestgestelde vragen. Heb je een andere vraag? Neem gerust contact op.

We do this through multiple channels, both online and offline. When thinking online, think of social media advertisements, Google ads, but also improving your website and increasing conversion. We are also happy to think about what we can do for you offline. Like cool flyer promotions! We deliver tailor-made solutions and do what suits your location!

We will of course go to great lengths to generate more members for your sports location. If it is the case that we are not a match or your investment is not profitable. Then we just stop. With us you are not committed to anything!

No, you are not committed to anything. You can decide to quit every month. But beware: this also stops the constant flow of new leads 😉

No, we only work with one party within a radius of 15 km. Competing with ourselves doesn’t seem like a good idea to us. We can’t be beat 😉

Brief summary

Van lead naar lid



We provide new potential customers for your sports location



We convert as many leads as possible into a physical appointment



Together we convert the appointment from lead to member

Throughout the Netherlands

Sterck throughout the country

Discover the community of fitness entrepreneurs who have embraced the power of Sterck throughout the Netherlands.

Je fitnesslocatie groeien in 90 dagen