When it comes to building muscle—or any fitness routine, for that matter—most people assume that more is more. More sets, more reps, more time in the gym must mean more gains. Right?
Not necessarily. In fact, new research from Florida Atlantic University’s Muscle Physiology Lab suggests otherwise. According to the findings, building strength and muscle isn’t about training harder—it’s about training smarter.
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Published in the sport and exercise science preprint journal SportRχiv, the study analyzed data from dozens of previous resistance training trials and reclassified sets into two distinct categories: “direct” sets, which targeted the exact movement or muscle being measured—like squats for leg strength—and “fractional” sets, which worked the same muscle group, but less directly (think: leg press for leg size).
From there, researchers ran statistical models to identify the point of “diminishing returns”—or when doing more sets no longer leads to meaningful improvement in strength or muscle growth. And it’s earlier than you’d think.
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You Only Need This Many Sets to Build Muscle, According to Science
According to the study, while more sets can help, it’s only up to a point. After that, the benefits plateau, and you enter the zone of diminishing returns. As for how many you actually need?
For strength gains—meaning you’re simply trying to get stronger—the sweet spot was just two direct sets per session. If your goal is muscle growth, however, you could benefit from up to 11 fractional sets per session. Beyond that, more isn’t necessarily better.
In other words, you don’t need marathon workouts to make meaningful progress, according to the study authors. “There is a positive dose-response relationship…but it exhibits diminishing returns,” they wrote. “More sets eventually stop being more effective.”
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Wait, What’s a Set?
In strength training, a rep (short for repetition) is one complete movement of an exercise—like a single pushup or squat. A set is a group of consecutive reps. So, if you do 10 squats in a row, that’s one set of 10 reps.
As Planet Fitness explains: “If your goal is to complete 20 pushups, you might break your workout up into two sets of 10 reps. This can help you effectively pace yourself.”
Most workouts involve multiple sets per exercise, with short rest breaks in between. How many sets you do determines your total training volume and plays a big role in building strength and muscle, which is exactly what this study is all about.
Direct Vs. Fractional Sets
Confused by the “direct” and “fractional” lingo? Here’s how to think about it: If your goal is building leg muscle, a squat would be considered “direct” because it works your whole lower body in a very targeted way.
A leg press, on the other hand, still works your legs—especially quads and glutes—but it’s more supported and doesn’t work as many stabilizing muscles. So it’s counted as a fractional set. It still helps with muscle growth, just not as directly as a squat.
Or, think of it like cooking. If your goal is to make spaghetti, boiling the pasta is a direct action—it’s essential and clearly moves you toward the final dish. Grating cheese or setting the table still contributes to the meal, but they’re not as directly tied to cooking the pasta itself. Those are fractional actions. It’s the same idea with exercises.
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How to Train Smarter, Not Harder, According to Trainers
While these findings are promising, it’s important to take any new research, especially a preprint, with a grain of salt. (Preprints haven’t yet been peer-reviewed or published in scientific journals that vet the methods and conclusions.)
To make sense of the “train smarter, not harder” approach, we asked certified personal trainers what they think—and how you can apply it to your routine, even with limited time.
Is less really more?
Is less really more? It absolutely can be. “This paper adds to a growing body of research that suggests that if we want to maximize our muscle strength, we don’t have to do very many sets,” says Luke Carlson, CPT, ACSM-EP,a fitness trainer, exercise physiologist and CEO and founder of Discover Strength. “Two sets for a muscle group really can maximize our muscle strength.”
Jesse Ramos Jr.,CPH, CHC, a certified health coach and fitness transformation specialist at BBT Fitness, agrees: “Two sets can be effective—especially when done close to failure and with intention—but that doesn’t mean two sets is always ‘enough.”
Translation? “This study shows you can make meaningful progress with minimal volume, which is great news for beginners and busy people. But for long-term strength development, most people will eventually need more volume,” Ramos explains.
In a way, you can think of the study covering two bases: Tips for beginners (two sets), and for advanced trainers (around 11). Which brings us to our next point…
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Is there really a “limit” for muscle growth?
Yes. In fact, Carson compares muscle growth to wringing water out of a towel.
“The first ‘set’ of ringing out the towel will probably eliminate 75% of the water. A second will likely eliminate another 20% of the water, and anything additional will give just a few percentage points of moisture reduction,” he says. “The same is true with additional sets. Most of our [muscle growth] improvements are stimulated in the first one to two sets we do for a muscle group.”
Is it 11 sets?
Not always. Sometimes it’s less, or very slightly more.
“More isn’t always better. There’s a sweet spot between stimulus and recovery,” Ramos explains. “Most of my clients see solid results in the eight to 12 set range per muscle group, per week. Going beyond that can help, but only if recovery, nutrition and intensity are dialed in. Otherwise, you risk burnout or injury.”
So while the study landed on 11 sets, the real answer varies. It’s likely somewhere in that range but truly depends on each individual
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How can you tell when you’ve hit the point of “diminishing returns”?
“Look at your recovery,” says Ramos. “If you’re adding more sets but your strength or energy is plateauing—or worse, going backward—you’ve likely gone past your threshold. I always say: if you’re adding more, you better be recovering more.”
At the same time, Carlson says that was the point of the study. “The trainee doesn’t need to decide for themselves,” he says. “The research study says we will hit the point of diminishing returns after just two to three sets.”
Training smarter, not harder, when you’re short on time
Pressed for time? You can still apply this approach. “Perform 10 to 12 exercises covering all of the major muscle groups with 1 to 2 sets per exercise,” says Carson. “For each exercise, aim for 8 to 12 reps to the point of muscle failure or very close to failure. This can be completed in 30 minutes to 45 minutes.”
Another option? Utilize compound movements like squats, presses and rows, and focus on intensity, adds Ramos.
“You don’t need 10 exercises—just 2 to 3 done well, with 2 to 4 solid sets each, will move the needle,” he says. “My go-to strategy? Short ‘micro sets’ of compound exercises that add up over time without stealing hours from your day.”
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Sources
- Is There Too Much of a Good Thing? Meta-Regressions of the Effect of Per-Session Volume on Hypertrophy and Strength. SportRχiv.
- Everything You Need to Know About Reps and Sets. Planet Fitness.
- Luke Carlson, CPT, ACSM-EP, a fitness trainer, exercise physiologist and CEO and founder of Discover Strength
- Jesse Ramos Jr.,CPH, CHC, a certified health coach and fitness transformation specialist at BBT Fitness