A New 12-Week Study Found That Just 1 Set to Failure Grew Pecs as Much as 3 Sets – Here’s What the Full Body of Research Says About Training Volume

Can you grow bigger muscles with just one set per exercise? A new study suggests you might — but the full answer is far more nuanced.

In the world of hypertrophy, training volume is a hotly debated topic, and this latest research adds an unexpected twist.

Today, we’ll break down exactly what the new study found, how it fits into the broader literature, and what it really means for your training.

If you’ve ever wondered whether doing more sets is worth your time — or if you’re missing out by doing too little — this deep dive is for you.

New Study: One Set vs. Three Sets of Pec Deck Flyes

A recent study examined how doing different numbers of sets affects muscle growth — using a clever within-subject design. Researchers had 15 untrained men train the pec deck fly twice per week for 12 weeks. Each participant trained one arm with one set per session (2 sets per week) and the other with three sets per session (6 sets per week). Importantly, all sets were taken to volitional concentric failure.

Muscle thickness was measured before and after the 12 weeks. Specifically, the study assessed two regions of the pectoralis major: the clavicular (upper) and sternocostal (middle/lower) heads. Surprisingly, both single and triple set conditions showed similar hypertrophy in both regions of the pec.

What the Results Seem to Show

• Both the clavicular and sternocostal portions of the pec grew similarly.
• There was no significant difference in muscle growth between performing one set or three sets per session.

Given prior research showing that higher volumes generally lead to more hypertrophy, these results may seem counterintuitive. But as we’ll explain, there’s more to the story.

Why the Results May Not Be What They Seem

Whenever a single new paper contradicts the trend of previous literature, it’s tempting to question the science entirely. Some call this “flip-flopping,” but experts warn against jumping to conclusions.

“This is not a case of science being unreliable, but simply a reminder of how complex it is,” says the team at House of Hypertrophy. “Single-study findings are like dots in a mosaic. You only see the full picture when zooming out.”

Sample Size and Random Variation

The study featured only 15 participants. With small numbers, the likelihood of random noise skewing the results increases significantly. Think of flipping a coin three times and getting heads each time — not because the coin is rigged, but because short sample sets are more volatile.

Other Limitations

Even within a within-subject design, there can be variables like limb dominance, measurement error, or different recovery between arms. It’s also unclear how lifestyle factors such as sleep, diet, or outside physical activity may have influenced the outcome for each limb.

What Larger Trends and Meta-Analyses Suggest

One paper does not disprove decades of research. Meta-analyses — which combine data from many studies — offer a clearer answer.

The latest meta-regression analyzing set volume and hypertrophy shows:

• More sets usually lead to more growth, though the returns diminish.
• The relationship isn’t infinite — doing 30 sets per muscle per week isn’t 10x more effective than doing 3 sets.
• Lower volumes can still result in meaningful gains, especially for beginners or during time-constrained periods.

In fact, the “sweet spot” for many people appears to fall in the range of 10–20 sets per muscle group per week, depending on experience, recovery capacity, and exercise selection.

Where Individual Differences Come In

Could it be that some people just respond better to fewer sets?

A 12-week study on unilateral leg training found that:

• A majority of participants grew more from three sets.
• Some had no difference between one and three sets.
• A few actually grew more with one set.

But the researchers cautioned that these apparent individual differences may not represent true biological differences — they could simply be noise from small sample sizes, measurement error, or external influences.

Still, the possibility of individual volume responsiveness remains intriguing. Some may thrive on lower volumes due to genetic or lifestyle factors (like stress or poor sleep), while others might require more sets to break through plateaus.

So, Should You Do One Set or Multiple?

If you’re short on time, there’s good news — low volume training can absolutely stimulate hypertrophy. For beginners or maintenance phases, one set per exercise done to failure may be enough.

However, if you’re recovering well and chasing optimal growth, chances are you’d benefit from doing more sets per muscle group per week. Aim to:

• Start with 10–12 sets per muscle group per week.
• Gradually increase volume if your recovery allows.
• Monitor your progress and back off if signs of overtraining appear.

What About Muscle Region Specificity?

This recent study also aimed to explore how different areas within a muscle might grow. Both the clavicular and sternocostal heads of the pec grew similarly during the pec deck exercise, challenging the idea that upper pecs are hard to target.

Still, this conclusion comes with caveats:

• They only measured one point within each region — not the entire muscle.
• Larger-scale studies dividing the pec into multiple measurement regions are needed to clarify nuances.

At present, exercises like the incline press are still a smart inclusion for upper chest development, based on anatomical understanding and electromyography (EMG) data.

The Takeaway: A Balanced Perspective on Volume and Hypertrophy

One set can build muscle — especially if taken to failure — but multiple sets tend to build more on average. That said, there’s no magic number. Here’s a practical approach based on the current science:

• Use scientific averages as your starting template, not a rigid rulebook.
• Adjust based on your recovery, lifestyle, and goals.
• If you’re making gains and feeling recovered, your plan is working.
• Stalled progress? It might be time to experiment with more volume.

As research continues to evolve — especially regarding region-specific hypertrophy and individual volume responsiveness — one thing is clear:

There’s no one-size-fits-all formula — just the ongoing pursuit of progress, backed by data.