First Principles
The simple laws your body follows to get stronger.
If you’ve ever taken a basic science class, you’ve heard of first principles.
A first principle is a foundational truth — something you can’t break down any further. It’s the bedrock everything else depends on.
In physics, one of the simplest first principles is this:
Gravity on Earth is constant.
No matter what you drop — a feather, a rock, or a rhino — gravity pulls them downward the same way every time.
Wind resistance might change how fast something feels like it falls (i.e. the rhino is heavy, so air resistance affects it less; the feather is very light, so air resistance slows it down more), but the underlying truth never changes.
Gravity sets the rules.
In cooking, a first principle is:
Acid, fat, salt, heat.
Every Master Chef learns these fundamentals because once you understand them, you can create anything — new dishes, improvisations, entire styles of cooking — without needing a recipe.
Strength training is the same way.
When you understand the first principles, everything becomes simpler — and you can adapt your training to any age:
You know what matters. You know what doesn’t. These are the laws your training must follow if you want your body to respond.
Everything else — volume, sets, reps, equipment — is secondary.
First principles of strength training
If gravity is the constant in physics, these are the constants in strength training — the laws that don’t change even when your life, schedule, stress level, or joints do.
They’re simple.
They’re unsexy.
They work at 25 and they work at 55.
Everything else is air resistance — it affects how training feels, but not how strength is built.
Here are the first principles your body actually responds to:
1) Your body adapts to patterns, not one-off efforts
A single workout is just an event.
A repeated workout becomes a pattern — and your body adapts to patterns.
2) Muscle strength comes from five core categories
Hinge
Squat
Push
Pull
Carry
All other lifts are variations of these categories.
3) Your body only adapts when it experiences a challenge above its normal level
Strength increases when the body senses a level of effort it isn’t accustomed to.
4) Muscles grow when they are asked to produce steady effort under control
Growth is driven by controlled resistance, not by exhaustion or speed.
5) Your body only uses the strength it feels safe using
If a position feels unstable, the body automatically reduces how much strength you can access.
Why these principles matter
Because they are always true.
Methods change as trends come and go.
Programs change every time a fitness influencer goes viral.
Equipment changes when engineering improves.
Your schedule, energy, and goals change as you age.
These principles don’t change; they apply regardless of how old you are, how your body looks, what season you’re in, or what your routine currently allows.
When conditions shift, the principles stay stable. That’s why they’re useful.
They give you a framework you can return to no matter what else is happening.
What these principles mean for your training
They make strength training easier to understand.
If the pattern repeats, your body will change.
If the movement fits into one of the five core categories, it builds usable strength.
If the effort is above what your body is used to, it creates a signal to get stronger.
If the effort is controlled and repeatable, the signal is clearer.
If the position feels stable, your body allows full strength; if not, it holds back automatically.
These principles give you a simple way to evaluate any workout or exercise:
Is it something I can repeat often enough to form a pattern?
Does it belong to a core movement category?
Is it noticeably more challenging than what I normally do?
Can I perform it with control from start to finish?
Do I feel stable in the position?
If the answers are “yes,” it will build sustainable, durable strength.
If one or more answers is “no,” it’s either not doing much, adding noise, or increasing your risk.
Principles turn training from guessing into understanding.
On Friday
I’ll show you how to use these first principles to build a simple, repeatable strength plan you can adjust to any week of your life.
Free subscribers will get the Friday preview. Paid subscribers get the full application.
Thanks for reading,
-Marek
