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Why 3in1Sports?

We are personally involved, committed, build on our experience and love to share our passion. We see sport as a supplement, not as the fulfillment of your life.

Our mission

One-to-one coaching, personal involvement, mutual respect and trust are the values of 3in1Sports. Based on a personal relationship we challenge you and motivate you to make your dreams come true.

Our vision

3in1Sports helps you personally, as a team and as a company to make your dreams in sports come true.

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How does an exercise test help you run faster?

How does an exercise test help you run faster? When translated into a training program, a test helps you to train smarter and better.

Bootcamp Munt

3in1Sports Bootcamp

Join the 3in1Sports Bootcamp in Utrecht and work on your physical and mental fitness!

Trainer Bert Flier

Personal Coaching

Personal Coaching means one-to-one guidance by Bert Flier so you have access to all knowledge of 3in1Sports.

Exercise test

During an exercise test we determine your metabolic profile and assess your trainability and training zones.

3in1Sports helps you personally, as a team and as a company to make your dreams in sports come true.

The mission of 3in1Sports is to let athletes shine, push boundaries and experience adventures.

More information?

Want to know if 3in1Sports is for you? Want to make an appointment for an intake or personal training program? Contact us, we love to hear from you!



    Your message:


    Our training plans are made available online through TrainingPeaks. TrainingPeaks also functions as your training log so that your coach can see how your training is progressing and make timely adjustments.

    Training camps

    During our training camps we take care of your every need. Our camps are led by experience trainers and stage the most beautiful locations. During a training camp you don’t need to worry about anything other than eating, training and resting.

    Group sessions

    Once a month 3in1Sports organises a group training, so that we can also see you in the water, on the bike or on foot. These group sessions are organised at central locations and are free for our athletes.

    Bert gives you the feeling that everything is possible and nothing is mandatory. The different levels and goals were taken into account as well as personal injuries, aches and other imperfections.

    Remco Palm

    A big thanks for the coaching to half Ironman Stein! Sometimes it was difficult to make the necessary time commitment, but this was truly one of the best things I have achieved in sports.

    Bob de Ruiter

    Based on the theme ‘sports and faith’ we wanted to excite our teenagers. With a professional speaker, who could speak from his experience. We invited Bert Flier. He talked about how he started triathlon and what God and sports mean to him. Based on statements, we discussed being a christian and engaging in professional sports, the tension between living for God and for sports, and about using your talents. It was an inspiring, educational and fun evening where we could ask serious questions and were challenged to make choices.

    Jeugdclub de Bouwsteen

    What an excellent training camp! Team spirit, scenic bike rides, beautiful accommodation, great views, healthy meals, everything is possible and nothing is mandatory. Very inspiring!

    Gert van Gerner

    Yesterday really had to kick the habit… The formula for the 3in1Sports training camps is special, where people of all kinds and levels come into their own.

    Berteke de Jong

    When I committed to your coaching last year I never thought I could make so much progress. It was an eye-opener in terms of structure, types of sessions and joy in training, but also in terms of lifestyle, nutrition and attitude to life.

    Alain van den Berg

    Thanks for the inspiring clinic! During the core stability training Bert knew how to make us feel muscles that we had long forgotten.

    Triathlonvereniging Heerenveen

    Sports became a real voyage of discovery for me. The result: I lost 10 kilos, went via the half marathon to the full marathon, then to the half Ironman… and this year on to the Ironman!

    Willeke van der Zand

    What a cool weekend it was, tough but oh so cool. We’ll be back next year!

    Marc and Carla Donkers
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