“You’re Not Actually Building Muscle” — But We Are. Here’s Why.
Most lifters are flying blind.
They’re chasing size without understanding what they’re growing. They’re grinding through volume without understanding the adaptation they’re causing. They’re training hard — but not training smart.
So here’s the truth:
There are two types of muscle growth — and 99% of lifters don’t know how to train for either properly.
Welcome to the world of myofibrillar vs sarcoplasmic hypertrophy — the real conversation behind size, strength, and why what you're doing might be wasting your time.
Myofibrillar Hypertrophy: Muscle That Performs
This is the gold standard. The “meat and potatoes” of performance.
Myofibrillar hypertrophy increases the number and density of contractile proteins (actin and myosin) inside your muscle fibers. These are the structures that actually generate force.
What you get:
Strength increases that carry over to real-world performance
Dense, athletic muscle that doesn’t fade when the pump wears off
Improved rate of force development and neural efficiency
This is what builds strongmen. Powerlifters. Athletes. Lifters who aren’t just big — they’re dangerous.
Sarcoplasmic Hypertrophy: The Overlooked Weapon
Now here’s where the story changes — and where most coaches stop thinking.
Sarcoplasmic hypertrophy increases the non-contractile volume of the muscle cell — the sarcoplasm — which includes glycogen, enzymes, fluid, and mitochondria.
No, it doesn’t directly make you stronger.
But that doesn’t mean it’s useless.
What you actually get:
Greater glycogen storage, which means more available energy for high-volume training
Enhanced muscular endurance and improved metabolic conditioning
Increased blood flow and capillarisation, improving recovery and nutrient delivery
A fuller, rounder look — the visual aesthetic of muscle mass
It’s a tool. And when you understand it, it’s a powerful one.
Science-Backed, Not Bro-Science
You might’ve heard:
“A meta-analysis says all rep ranges build muscle!”
Yes — and we’ve read it.
The 2017 Schoenfeld meta-analysis found that hypertrophy can occur across rep ranges from 5 to 30, as long as sets are taken near failure and volume is equated.
But here’s the thing:
That research measured muscle size, not muscle composition.
It didn’t tell us what kind of tissue was growing — just that growth occurred.
And more recent research (like Haun et al., 2019) shows that excessive volume may lead to sarcoplasmic expansion without proportional increases in myofibrillar proteins — meaning it’s not all contractile gains.
So yes, you can grow muscle in many ways —
But at JMSTRENGTH, we’re more interested in what that growth actually does.
The JMSTRENGTH Difference: We Use Both — Intentionally
Most coaches stumble blindly into one adaptation or the other.
We don’t.
At JMSTRENGTH, we understand:
When to chase sarcoplasmic hypertrophy to improve work capacity, glycogen stores, and recovery
When to shift gears into myofibrillar-dominant training to build pure force-producing machinery
How to periodise both styles within a performance-focused block
And when to avoid one altogether based on your sport, injury risk, or recovery status
We don’t guess. We program with precision.
That’s why our athletes don’t just get big — they get better.
TL;DR: Are You Just Inflated, or Actually Built?
Here’s the main point, without the fluff.
| Type | What It Builds | Benefits | When We Use It |
|---|---|---|---|
| Myofibrillar | Contractile tissue (actin/myosin) | Strength, density, neural adaptation | Main driver in strength phases, joint integrity etc. |
| Sarcoplasmic | Fluid, glycogen, enzymes | Size, endurance, blood flow, glycogen storage | Strategic work capacity, metabolic priming, recovery phases etc. |
Final Word
Anyone can make you sweat.
Anyone can get you sore.
Anyone can make your arms look bigger in a mirror.
But not everyone can build muscle that performs — and knows when to build the right kind.
That’s what we do.
Join the JMSTRENGTH SYSTEM™