Muscle Growth Doesn't Work Like You Think: Here's How It Actually Happens
Whether you want a bigger butt or yoked shoulders, building muscle is how you get there. So, if your fitness goals are tied to a “looks” outcome, you are going to want to read this one.
You’ve probably heard fitness influencers and gym bros talk about rep ranges and maxouts for growing muscle. 5x5s, 8-12 rep range, 70% of max, etc. We’ve been told for so long that high weight and lower reps are best for building muscle. But that’s not what actually builds muscle.
It’s volume. Total volume builds muscle. That’s it. In this blog post, we explore what the research says—and what it doesn’t—when it comes to building muscle.
What Science Says
A 2000 study (Weiss et al.) trained 3 groups across three different rep ranges and found that muscle growth occurred in all three groups, although the strength adaptations differed. Another study done in 2014 (Schoenfield et al.) compared heavy and medium loads and found similar muscle gains between the two groups. Another study (Roie et al.) published the same year showed no difference in hypertrophy between groups that trained at 80% of their 10-rep max and 20% of their 10-rep max. The conclusion? It’s volume that matters—not rep ranges, percent max, or bro science.
Calculating Volume
So how do we increase volume? Here’s where math comes in. And you never thought you’d need it after high school… Here’s the formula:
Weight lifted
x
Number of reps
x
Number of sets
=
Volume
Volume Multipliers
Want to supercharge your results? There are a few ways. Slow tempo lifting and blood flow restriction (BFR) are both ways to get more out of your lifting. Let’s explore further.
Tempo Lifting
Time under tension builds muscle. It’s an uncalculated variable that has fallen out of vogue recently, but that doesn’t mean you should ignore it.
The best thing about using slow tempos and isometric holds in your lifts? It lets you get away with using less weight. This is great for people who don’t have access to heavy weights, people recovering from injuries, and people new to lifting weights. It just makes things more accessible.
Want to learn everything about using specialized tempos in your lifting? Check out this post.
BFR Training
Blood flow restriction (BFR) training traps blood and lactate in muscles, allowing new blood to rush in and facilitate a changeover process once blood flow is restored. It has also been shown to increase human growth hormone (HGH), which boosts hypertrophy. It is often used in rehabilitation settings but is being used increasingly by athletes and everyday lifters. There is one caveat: it can be hard to determine the right amount of blood flow to restrict, with too much BFR resulting in possible injury and too little resulting in, well, absolutely nothing. Since it is very difficult to use low-tech options that do not calculate the pressure, and learning to calculate pressure is highly specialized, using BFR cuffs like Smart Tools or SAGA that use an app and state-of-the-art technology is considered a must by coaches and physical therapists.
Volume For the Win
While all the bro scientists and influencers are out there chasing trends, you could be at the gym making gains. Use your volume calculations to keep progressing, no matter the number of sets you do or the rep ranges you use. Just do what feels good for your body and moves you forward.
A Challenge: Are You Up for It?
Speaking of gains, I’ve built a 28-day challenge all around using time under tension as a volume-building variable.
If you want a structured, progressive, beginner‑friendly program that takes all the guesswork out of getting in better shape, this challenge was built exactly for you. It’s simple, effective, and designed to help you build a stronger, more powerful backside that actually shows up in real life.
Open only four times a year.
