Five years ago I ran my first 100 kilometres in Vondelpark in Amsterdam.

No mountains, no forests. Just 3-kilometre laps, for ten hours. The same circle over and over again. And that was exactly where the confrontation lay. Because the less the outside world changes, the more visible your inner world becomes. Perhaps the same is true for leadership.

We often talk about growth as if it is something big and linear. A vision, a breakthrough, a courageous decision. In reality, growth often begins at a subtler moment: when you feel that the circle you are moving in has become too small. A comfort circle is not wrong. It is the place where you build, learn, practise and develop confidence. But what helps you at first can later start to limit you. What was once growth can, at a certain point, mainly become repetition. And that is a difficult point. Because from the outside, such a circle often looks perfectly fine. You function. You perform. You know what you are doing. You might even be appreciated for it. And yet deep down you can feel: I am no longer growing here.

For me, that is where leadership begins. With honestly recognising that something that feels safe is not necessarily still right. Those 100 kilometres also taught me that growth rarely feels like one big leap. They were not heroic kilometres in a straight line. They were small loops. Returning to the same point. Setting off again. Development often works that way too. You keep returning to the same themes: doubt, courage, discipline, surrender. Only each time at a deeper level. You do not move in a straight line, but in circles. It is precisely at the edge of such a circle that you meet yourself.

There you hear your inner dialogue.
 There you notice how you react when control falls away.
 There it becomes visible which stories about yourself you have come to believe. Many of our limits feel objective, while they are often connected to identity. Sentences like: this does not suit me, this is just who I am, this far and no further. They sound logical, but very often they are not. Three years before I ran those 100 kilometres, I would probably have said that something like that was impossible. Not for someone else, but for me. That is what comfort sometimes does: it disguises an old limit as truth.

What also stayed with me that day was how rarely we truly push such limits entirely alone. My pacers, friends, my mother and her husband: they carried something with me that I ultimately had to do myself. The same applies to leadership.

Good leaders do not simply push people out of their comfort zone. They create an environment in which someone dares to step into a next circle. With enough safety not to become paralysed, and enough tension to get moving. Perhaps comfort is therefore not the enemy. Perhaps it is mainly a signal.

The real question is not whether a circle is safe.
The question is: is it still serving you?

Does this circle still bring growth, sharpness and life?
 Or is it mainly keeping an old version of yourself in place? When I now think back to those 100 kilometres, this is mainly what I see: Leadership asks that you keep sensing when an old form has become too small. That you do not wait until life pushes you out of it, but learn to recognise when it is time to step into a new circle yourself.

Because what still feels comfortable today,
 can easily become the boundary tomorrow of who you are becoming.