5 Science-Backed Reasons Your Chest Won’t Grow
Aside from stubborn calves, there’s one muscle group that seems to be hard to build for even the most dedicated lifters: the chest. You bench. You press. You even throw in cable flyes for good measure. And yet—nothing. No mass, no pop, no pec shelf to speak of.
While you could blame your parents (yes, genetics play a small role), there’s a good chance your chest is lagging for far less mysterious reasons. Recently, Mike Israetel, Ph.D., exercise scientist and co-founder of Renaissance Periodization, interviewed sports scientist Pak Androulakis-Korakakis, Ph.D., to break down the five common mistakes that explain why so many guys struggle to grow their pecs.
Spoiler: They’re not exactly groundbreaking, but they are probably what’s holding you back from the ideal chest.
Related: 50 Best Chest Exercises of 2025 to Build Your Pecs and Pushing Power
5 Reasons Your Chest Isn't Growing
1. Training Volume
For years, there’s been a debate: Should you lift heavy or crank out more volume? While technically you can (and probably should) do both in the name of hypertrophy, Androulakis-Korakakis says bumping up your volume could be the real game-changer when it comes to building muscle.
"If chest is one of these lagging body parts for you, hitting it with 20 or even 30 sets per week is a good educated bet," he says. When it comes to your session training volume, you don't want to do everything in one session, so when I say 20 to 30 sets, ideally split those in two to three sessions so you can get high-quality sets very close to failure."
2. Exercise Selection
Compound exercises are a must in every man’s routine. They hit multiple muscle groups, boost your pressing power, and build serious strength. But if you’re trying to zero in on your chest—and only your chest—then isolation moves aren’t optional, they’re essential.
"When it comes to bringing up your chest as a lagging body part, you want to keep roughly 50 to 60 percent of your exercises as isolation exercises," Androulakis-Korakakis adds. "Meaning things like double flies, cable flies, machine flies, pec-deck...any exercise that pretty much isolates the chest, so you can make sure that your chest is getting as much stimulus as possible."
3. You Train Too Light
It’s tempting to go lighter, especially when you’re chasing higher volume. But according to Androulakis-Korakakis, that’s one of the biggest reasons your chest might not be growing. When it comes to building muscle, lifting to—or at least close to—failure is key. If you’re not pushing yourself there regularly, you could be leaving gains on the table.
4. You're Not Using Your Bodyweight
According to Androulakis-Korakakis, bodyweight exercises are one of the most underrated types of exercises for building size.
They offer an "amazing stretch, barely any warm-up required, super easy to progress, even if you're an advanced lifter, and in general, easy exercises that you can sprinkle on top of other sessions to get more volume," he says.
5. You Don't Emphasize the Deep Stretch
Pausing during sets has long been debated—is it actually effective, or just a way to look like you’re grinding harder? According to Androulakis-Korakakis, it’s more than just show. Strategic pauses can boost time under tension, which has quite literally been shown to drive muscle growth.
"Choose exercises that place a lot of tension in the stretch and do your best to pause stuff in the stretch," he says. "The pause is not going to take away from your gains, and it will likely allow you to be a bit more efficient with the weights that you use. It will make the exercise harder, and it will give you more space to progress."