Mental Fitness: The Overlooked Muscle That Needs Training Too

Inspired by Rob Shaul’s “Mental Fitness” Experiment

A few years back, strength coach Rob Shaul ran a simple experiment on himself: could he complete long, grindy gym sessions without checking the clock? Turns out, that one small act unlocked a world of insight into what he calls mental fitness. The takeaway? Our minds need training just like our muscles do.

We coaches, athletes, and everyday grinders all talk about mental toughness. But Shaul’s article, published on the Mountain Tactical Institute’s website, reframes the conversation. Mental fitness isn’t a badge of honor; it’s a skill that can be built, lost, and maintained.

Let’s explore mental fitness and how it can be trained like squats or VO2 maxes.

Mental fitness and toughness has been a focus of mine for the last fifteen years, ever since I realized just how much my self-talk influenced my performance - in the gym, in competition, and in life. That insight became the spark for a personal journey that continues to this day. It's the main reason I seek out physical challenges that push my limits. These aren’t just workouts; they’re life-changing experiences that sharpen both body and mind.

I often say, 'The hardest thing you’ve ever done is the hardest thing you’ve ever done.' In other words, doing truly hard things changes you. Those who have stepped into real discomfort - who have chosen to struggle - are fundamentally different from those who haven’t. And that difference matters.

What Is Mental Fitness?

Mental fitness is your ability to handle discomfort, stay focused, and keep going when you want to quit. It's not about being born tough. It's about building resilience through repeated exposure to challenging experiences.

Shaul prefers “fitness” over “toughness” because the former is dynamic, it can be improved. It can also decondition. Just like your deadlift drops after a vacation, your tolerance for grind fades without regular mental reps.

Mental Fitness Is Mode Specific

One of the most important lessons from Shaul’s article is that mental fitness doesn’t always transfer between activities. He tells the story of an elite alpinist who crushed life or death climbs in the mountains but struggled during his first gym based conditioning workout. Why? Because the mental strain of burpees and sprints was a new mode, one his mind wasn’t calibrated for yet.

The second time around? He crushed it.

This shows how mental fitness is context specific. It takes time to adapt to new stressors. Even inside the gym, switching from strength training to sprints or from running to rucking can feel like a psychological gut punch. The discomfort is different, and so is your reaction to it.

You Have to Train It and Maintain It

Mental fitness doesn’t stick around just because you once suffered through Murph in a 20-pound vest.

Shaul notes how even elite military operators, people who’ve passed the world’s hardest selection courses, can lose their edge if they stop doing hard things. Comfort is the enemy. Doing only what you like, even at high intensity, can create a mental dead zone where growth stalls.

The takeaway? Just like muscles, the mind needs regular stress to stay strong. You have to do hard things, especially things you’re not good at or don’t like.

The Self-Control Tank

Part of mental fitness is self-regulation. Shaul’s experiment involved not looking at a clock during a 30-minute grind session. His internal battle, counting songs, watching training partners for clues, and even closing his eyes to avoid sneaking a peek, is a masterclass in how hard it is to override our instincts.

He compares it to something Aristotle once wrote: integrity becomes easier as you practice it, but it still requires constant vigilance. Modern psychology backs this up. Studies on self-control suggest that we wake up with a “tank” of restraint, which drains throughout the day. Skipping the donut at 8 a.m. is easy. Resisting the nightcap after a 12-hour day? Not so much.

This isn’t a flaw. It’s how our brains work. The good news? Self-regulation is trainable, just like anything else in fitness.

Is There Carryover to Real Life?

So, does mental fitness in the gym transfer to life outside it? Shaul says yes, with caveats.

His mountain athletes report hearing his coaching voice in their heads during grueling climbs. Military clients say gym-based selection simulations hardened them for the real deal. That’s a real-world transfer.

But does this kind of fitness help with moral or emotional challenges? Like choosing honesty when it’s hard or staying calm in a heated conversation?

The jury’s still out. Some psychologists argue that mental grit in physical training doesn’t always mean integrity or compassion. Others suggest practicing discipline anywhere can build your capacity to handle discomfort and make better decisions.

How to Train Mental Fitness in Your Gym

Here are some strategies inspired by Shaul’s work and broader research:

1. Deliberate discomfort: Do workouts without music. Remove the clock. Use odd objects.

2. Switch training modes: Don’t get too comfortable with your programming. Move between strength, endurance, and conditioning regularly.

3. Self-imposed constraints: Try long grinds without breaks, silent workouts, or partner challenges in which one person rests only when the other completes a task.

4. Track mental wins: Journaling your reaction to hard sessions can build awareness and progress over time.

5. Coach it like you program it: Don’t just bark at athletes to “toughen up.” Give them tools to build mental stamina, like pacing strategies, breathing drills, or reframing challenges.

Final Thought

Mental fitness isn’t just about pushing through pain. It’s about awareness, regulation, and deliberate practice. Just like physical gains, it requires training cycles, progression, and constant reinforcement.

As Shaul puts it: “The goal is not to look at the clock, but to not think about the clock at all.”

Whether you’re coaching athletes, training yourself, or just trying to be a better human under stress, don’t ignore the mental side of fitness. It might be the most important muscle you train.

Source:
Shaul, Rob. Mental Fitness. Mountain Tactical Institute, 2017. https://mtntactical.com/knowledge/mental-fitness/