The approach

Not a toolkit.
A transformation.

Mindboxing is built on a simple observation: most people in high-performance environments don't struggle because they lack skills. They struggle because they haven't fully understood their own relationship with pressure, failure, and expectation.

The Mindboxing method creates the conditions for that understanding — through honest reflection, structured challenge, and sustained accountability.

The Three Batteries® Method

Connecting Mind, Heart & Body

Mindboxing® is not about symptom relief. It is about getting to the source. Most people who struggle with performance, stress or energy don't have a knowledge problem — they have a balance problem. Between what they give and what they recover. Between how they think, how they feel, and how they live physically.

The Three Batteries® method, developed by Jan Sleijfer, addresses exactly that. Three interconnected sources of energy — when one runs low, the others follow. When all three are charged, sustainable performance becomes possible.

Three Batteries® is a registered method developed by Jan Sleijfer · mindboxing.net

How we work together

The process

Begin with a conversation

Leadership · May 2026

Who coaches the people at the top?

The Gallup 2026 report reveals something that should concern every organisation — and every leader.

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One number stood out.

20%.

That's the share of employees who are engaged at work. The lowest since 2020. Down for the second consecutive year.

But this is the finding that really landed for me.

Leaders report higher life satisfaction than those they lead. And yet — compared to individual contributors — they are significantly more likely to report stress, anger, sadness, and loneliness on any given day.

Higher up. Better story. Harder days.

That gap between how we think our life is going and how we actually experience it day to day — that's the territory I've worked in for 30 years. Most of the leaders I've coached weren't struggling with performance. They were struggling with what high performance costs them.

The leadership paradox

Gallup calls this the gap between the reflective self and the experiencing self. How we think our life is going versus how we actually feel. For leaders, that gap is wider than for anyone else in the organisation.

The largest single-year drop in manager engagement was five points — between 2024 and 2025. Larger spans of control, pressure around AI adoption, organisational flattening. Managers are being asked to do more with less support themselves. This speaks directly to the kind of client I work with most: high-functioning people who carry a lot, show up reliably, and whose internal erosion goes unnoticed — not least by themselves.

Engagement as protection

One finding is worth sitting with. Engaged managers experience all negative emotions at significantly lower rates than disengaged ones. Not because the pressure disappears. But because meaning changes the weight of it.

That's not soft science. That's a finding from the world's largest ongoing study of employee experience.

The question I keep coming back to

We invest heavily in developing leaders. We give them tools, frameworks, and training. What we give them far less of is space — space to be honest about what the role is actually costing them, and support to work through it before it becomes a crisis.

Who coaches the people at the top?

In my experience, not enough people do.

Still learning. Still moving forward.

Resilience · March 2026

Burnout isn't a productivity problem

We keep trying to fix it with better time management. The research — and 30 years of practice — suggests otherwise.

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Your most committed employees are your highest burnout risk.

Not the disengaged ones. Not the clock-watchers. The people who care deeply about their work — who stay late, absorb pressure quietly, and never quite switch off.

This is the burnout paradox. And it's one that most organisations are still not equipped to see.

What the research actually says

Christina Maslach, who first studied burnout in the 1970s, made a point that still doesn't get enough attention: burnout is not a personal failing. It is a response to chronic, poorly managed work stress. The problem lives in the system, not the individual.

Fifty years on, that distinction still doesn't receive the attention it deserves.

Research consistently shows that passion and overcommitment are risk factors, not protections. People who feel strongly about what they do tend to over-invest emotionally. And because they care, they are also the last to admit they are struggling.

The warning signs we miss

These individuals often remain high-functioning right up until the point they don't. There are rarely obvious warning signs. By the time someone is signed off, the cost — in lost productivity, recruitment, and team disruption — is already significant.

What makes it harder is that the people most at risk are often also the most reluctant to ask for help. They have built their identity around being capable. Struggling feels like failure.

What actually helps

The solution is not better time management. It's not a wellness app or a Friday afternoon off.

It starts with honest conversations — about what the work is actually costing, about where the energy is going, and about whether the environment is asking more than it is giving back.

In my experience, the leaders and professionals who navigate pressure well are not the ones who feel less of it. They are the ones who have developed a clearer, more honest relationship with themselves. They know what depletes them. They know what restores them. And they act on that knowledge before it becomes urgent.

That's not soft skill work. That's sustainable performance.

Still learning. Still moving forward.

Mental Performance · April 2026

The gap between knowing and doing

Most high performers already know what they should do. The question is never the knowledge.

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Most high performers already know what they should do.

They know they should delegate more. Sleep more. Say no more often. Have the difficult conversation they've been avoiding for three weeks.

The question is never the knowledge. It's what gets in the way of acting on it.

The knowing-doing gap

In thirty years of coaching, I have rarely met a client who lacked information. What they lacked was the ability to act consistently on what they already knew — particularly under pressure, particularly when it mattered most.

This gap between knowing and doing is not a willpower problem. It is not a motivation problem. It is almost always a relationship problem — specifically, a relationship with yourself that hasn't been examined closely enough.

What actually closes the gap

The gap closes when people develop genuine self-awareness — not the kind that involves knowing your Myers-Briggs type, but the kind that allows you to notice, in real time, what is actually driving your behaviour.

Why do I avoid this conversation? What am I actually afraid of? What story am I telling myself about why now isn't the right time?

These are not easy questions. But they are the right ones. And in my experience, the people who are willing to sit with them — honestly, without rushing to a conclusion — are the ones who make the changes that last.

More information was never the answer. It rarely is.

Still learning. Still moving forward.

Self-awareness · February 2026

The silence we don't notice

We notice the silence from others. But rarely the silence within ourselves.

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We notice the silence from others immediately.

The colleague who stops asking questions. The team member who used to challenge ideas and no longer does. The partner who has gone quiet in a way that feels different from ordinary quiet.

But the silence within ourselves — that one we tend to miss entirely.

The noise we call normal

We move through our days — checking in, showing up, giving — and somehow never stop to ask ourselves the questions we so freely ask of others. How are you really doing? What do you actually need right now? When did you last feel genuinely energised by your work?

We have become remarkably skilled at staying busy. And busyness, I've noticed, is one of the most effective ways of not having to listen to yourself.

What the silence is trying to say

In my experience, the internal silence — the one that comes before disengagement, before exhaustion, before the moment someone finally admits they are not alright — is rarely sudden. It builds gradually. And it almost always carries information, if we are willing to slow down enough to receive it.

The question I often ask clients early in our work together is simple: when did you last do nothing, and feel comfortable with it?

The answer, more often than not, tells me everything I need to know.

Stillness is not the absence of productivity. It is the precondition for it.

Still learning. Still moving forward.

Pressure · January 2026

Mental fitness isn't built by avoiding pressure

Pressure reveals character. But it doesn't build it by itself.

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There is a version of resilience coaching that is, essentially, about avoidance.

Reduce your stress. Set better boundaries. Say no more often. Protect your energy. All reasonable advice. None of it, on its own, builds mental fitness.

Mental fitness is built under pressure. Not around it.

What pressure actually does

Pressure is a reveal mechanism. It shows you who you are when the scaffolding comes down — when you can't rely on routine, on preparation, on the version of yourself that performs well in comfortable conditions.

But pressure reveals character; it does not build it by itself. The building happens in the space between challenge and response — in what you do with what you notice, in whether you have the self-awareness to learn from the experience rather than simply survive it.

The missing ingredient

The leaders and athletes I've worked with who perform consistently well under pressure share one characteristic: they have a relationship with themselves that is honest enough to be useful. They know their patterns. They know their triggers. They know what they look like when they are at their worst — and they have practised the art of catching themselves early.

That is not something you develop by reducing pressure. It is something you develop by learning to work with it.

The goal is not to feel less pressure. The goal is to become someone who responds to it well.

Still learning. Still moving forward.

Coaching · December 2025

What makes coaching actually work

After 30 years, I've noticed something consistent about the clients who grow most.

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After thirty years, I've noticed something consistent about the clients who grow most.

It's not the ones who arrived most motivated. It's not the ones with the most pressing problems, or the clearest goals, or the most sophisticated understanding of their own psychology.

The clients who grow most are the ones who were most willing to be honest.

What honesty actually requires

I don't mean honesty in the simple sense of not lying. I mean the harder kind — the willingness to say things out loud that you have been quietly knowing for some time, but haven't quite allowed yourself to fully acknowledge.

That this role is no longer right for you. That this relationship has been costing you more than it gives. That the version of success you have been chasing is not actually yours. That you are more tired than you have admitted, even to yourself.

What good coaching creates

Good coaching doesn't create honesty. It creates the conditions in which honesty becomes possible — and then useful. A space that is safe enough to be real in, and structured enough that what emerges from that reality can be worked with.

The coach's job is not to have the answers. It is to ask the questions that the client hasn't been asking themselves — and to stay in the room while they find out what the answers actually are.

That, in my experience, is what makes coaching work. Not the framework. Not the methodology. Not the credentials on the wall.

The willingness, on both sides, to be honest about what is actually happening.

Still learning. Still moving forward.