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Our services

Our services are there to help you realize your potential, tailored to your level and personal goals.

Personal coaching

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

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Taeru Triathlon Camp

Taeru | 3in1Sports | Innerme triathlon camp

From 13-17 May 2024, 3in1Sports organizes with Taeru and Innerme a 5-day all-in triathlon camp. Subscribe now!

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Exercise test

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

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Notitieblok, Pen En Laptop

Coaching call

If you have a training-related question that you would like to discuss one-on-one with an expert, book a coaching session.

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Bootcamp Munt

Bert's bootcamp

Join Bert’s Bootcamp in Utrecht and work on your physical and mental fitness.

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Run In The Morning

Training Plan

Use our expertise to get your personalised Training Plan.

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About us

The goal of 3in1Sports is to make athletes shine, push their boundaries, and experience adventures.

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.

Read about sports and health trends first-hand from a multiple Dutch triathlon champion, in the regularly updated…



Of our customers

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
Personal coaching

Last year I was coached by Bert to improve my running. Bert’s insights provided interesting, new information about competitive running and diabetes. I learned a lot about the possibilities of controlling my blood sugar level in training and racing. This provides a great advantage during racing for both diabetics and non-diabetics.

Erwin van de Werken
Personal Coaching

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

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
Personal coaching

Triathlon has become an essential part of daily life for me, next to work and family. If you add triathlon correctly to the mix, it will also improve you in other parts of life. Training and racing will bring you more than just exercising. With Bert as a coach I have the personal click to help me achieve balance, which is essential for me.

Remco Palm
Training camp Mallorca

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
Personal coaching

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
Training camp Ardennes

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
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