New research from Florida Atlantic University has just dropped a bombshell that could revolutionize how lifters approach their training splits.
Published in Sports Medicine, this massive meta-analysis analyzed 67 studies involving over 2,000 participants to decode the precise dose-response relationship between training volume, frequency, and results.
If you’ve ever wondered whether you’re doing too many—or too few—sets per week, this study offers concrete answers backed by hundreds of data points.
Lead researcher Joshua Pelland and his team at the Muscle Physiology Laboratory discovered something surprising: the optimal training approach for building muscle differs dramatically from what maximizes strength gains.
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Volume Drives Gains—But With Diminishing Returns
The research team found that increasing weekly set volume boosts both muscle growth and strength with 100% posterior probability—meaning the evidence is essentially undeniable.
However, the relationship isn’t linear. Both hypertrophy and strength gains follow a curve of diminishing returns, but strength plateaus far more aggressively than muscle size.
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This challenges conventional wisdom suggesting identical programming for strength and hypertrophy goals.
Direct vs. Indirect Sets: The Missing Variable
What makes this study groundbreaking is how researchers classified training volume.
Rather than simply counting total sets, Pelland’s team distinguished between direct sets (exercises specifically targeting measured muscles) and indirect sets (exercises with partial carryover).
They developed a “fractional” quantification method assigning values:
- Direct sets: Full value (1.0)
- Indirect sets: Half value (0.5)
- Unrelated sets: Zero value (0)
This approach proved superior to previous methods that treated all sets equally, regardless of specificity.
For example, bench press would count as 1.0 for pectoral measurements but only 0.5 for triceps measurements, since it indirectly trains that muscle group.
If you want something simple that actually works, this is one of the most effective tools I’ve used to build strength, conditioning, and endurance without needing a full gym setup.
- Full-body training with one weight using swings, squats, and presses
- Solid cast iron build that feels stable and lasts for years
- Comfortable grip that makes high-rep workouts easier to handle
Frequency Matters More for Strength Than Size
Perhaps the study’s most surprising finding concerns training frequency—how many times per week you train each muscle group.
For muscle hypertrophy, the effect of increased frequency showed less than 100% probability of meaningful impact, suggesting compatibility with negligible effects when volume is equated.
Translation: hitting muscles more frequently per week doesn’t necessarily grow them faster if total weekly volume remains constant.
However, strength gains told a completely different story.
The posterior probability for strength was 100%, suggesting strength gains increase with increasing frequency, albeit with diminishing returns.
This means practicing lifts more often throughout the week significantly enhances strength development, likely due to improved motor learning and neuromuscular adaptations.
Practical Application: Split Your Strength Work
Athletes chasing powerlifting or Olympic lifting PRs should prioritize higher training frequencies for competition movements.
If you want something simple that actually works, this is one of the most effective tools I’ve used to build strength, conditioning, and endurance without needing a full gym setup.
- Full-body training with one weight using swings, squats, and presses
- Solid cast iron build that feels stable and lasts for years
- Comfortable grip that makes high-rep workouts easier to handle
Instead of squatting once weekly for 10 sets, distributing that volume across 2-3 sessions produces superior strength adaptations.
Bodybuilders focused purely on hypertrophy have more flexibility, as muscle growth responds well to both high-frequency and lower-frequency approaches when volume is matched.
The Study’s Massive Scale and Methodology
This wasn’t some small pilot study with 20 college students.
Pelland and colleagues analyzed 67 resistance training studies encompassing 2,058 participants (79.1% male, 20.9% female) with an average age of 25 years.
The research team performed multi-level meta-regressions—sophisticated statistical modeling that accounts for numerous variables simultaneously.
All models were adjusted for intervention duration and training status, preventing confounding factors from skewing results.
If you want something simple that actually works, this is one of the most effective tools I’ve used to build strength, conditioning, and endurance without needing a full gym setup.
- Full-body training with one weight using swings, squats, and presses
- Solid cast iron build that feels stable and lasts for years
- Comfortable grip that makes high-rep workouts easier to handle
Every contributing study underwent rigorous classification, with researchers meticulously categorizing each set as direct, indirect, or unrelated to outcome measurements.
Why Previous Research Missed the Mark
Earlier meta-analyses on training volume produced inconsistent findings, leading to ongoing debate within exercise science.
Pelland’s team identified the problem: treating all sets as equal dramatically oversimplifies dose-response relationships.
A set of leg extensions contributes differently to quadriceps hypertrophy than a set of squats, despite both involving the quads.
By implementing the fractional quantification approach, researchers achieved far more accurate predictions of training adaptations.
Real-World Programming Recommendations
Based on these findings, lifters should structure programs according to primary goals:
If you want something simple that actually works, this is one of the most effective tools I’ve used to build strength, conditioning, and endurance without needing a full gym setup.
- Full-body training with one weight using swings, squats, and presses
- Solid cast iron build that feels stable and lasts for years
- Comfortable grip that makes high-rep workouts easier to handle
For Maximum Muscle Growth
- Prioritize total weekly volume with direct exercises targeting desired muscle groups
- Don’t obsess over frequency—2-3 times weekly per muscle works as well as higher frequencies when volume matches
- Push volume progressively but recognize diminishing returns beyond certain thresholds
- Count indirect volume at approximately half value when planning total workload
For Maximum Strength Development
- Distribute volume across higher frequencies—practice competition lifts 3-4+ times weekly
- Recognize volume exhibits sharper diminishing returns for strength than hypertrophy
- Emphasize movement specificity—direct practice of tested lifts matters immensely
- Balance volume carefully as excessive sets yield progressively smaller strength improvements
The Diminishing Returns Reality
Both muscle and strength gains follow non-linear curves, but the degree differs substantially.
Hypertrophy continues responding favorably to increased volume even at higher set counts, though gains per additional set gradually decrease.
Strength improvements plateau much faster, with pronounced diminishing returns setting in earlier.
This explains why elite powerlifters don’t simply perform enormous volumes of competition lifts—the return on investment drops off steeply beyond moderate volumes.
Instead, they strategically distribute moderate volumes across frequent training sessions, maximizing neural adaptations without excessive fatigue accumulation.
Individual Response Variation Still Exists
While meta-regressions reveal population-level trends, individual responses vary considerably.
If you want something simple that actually works, this is one of the most effective tools I’ve used to build strength, conditioning, and endurance without needing a full gym setup.
- Full-body training with one weight using swings, squats, and presses
- Solid cast iron build that feels stable and lasts for years
- Comfortable grip that makes high-rep workouts easier to handle
Factors including genetics, recovery capacity, nutrition, sleep quality, and training history all modulate how someone responds to specific volumes and frequencies.
These findings provide evidence-based starting points rather than rigid prescriptions.
Lifters should use this research as a framework, then adjust based on personal response, recovery, and progression.
Implications for Program Design
This research validates several increasingly popular training approaches while challenging others.
High-frequency powerlifting programs gain scientific support, as repeated practice of competition movements clearly enhances strength beyond what volume alone predicts.
Bodybuilding “bro splits” remain viable for hypertrophy, since frequency matters less when total weekly volume per muscle group is adequate.
If you want something simple that actually works, this is one of the most effective tools I’ve used to build strength, conditioning, and endurance without needing a full gym setup.
- Full-body training with one weight using swings, squats, and presses
- Solid cast iron build that feels stable and lasts for years
- Comfortable grip that makes high-rep workouts easier to handle
Upper/lower and push/pull/legs splits offer balanced approaches suitable for both strength and hypertrophy by providing moderate frequency with manageable session volumes.
The key insight: match training frequency and volume distribution to your specific adaptation goals rather than following generic advice.
Periodization Considerations
Understanding these dose-response relationships also informs periodization strategies.
During hypertrophy phases, lifters can accumulate higher volumes at lower frequencies without compromising results.
When transitioning to strength-focused blocks, reducing per-session volume while increasing frequency optimizes neural adaptations.
This approach manages fatigue while maximizing specific adaptations aligned with current training goals.
If you want something simple that actually works, this is one of the most effective tools I’ve used to build strength, conditioning, and endurance without needing a full gym setup.
- Full-body training with one weight using swings, squats, and presses
- Solid cast iron build that feels stable and lasts for years
- Comfortable grip that makes high-rep workouts easier to handle
What This Means Moving Forward
Pelland and his research team have provided the fitness community with unprecedented clarity on training dose-response relationships.
By distinguishing between direct and indirect training volume and separately analyzing effects on hypertrophy versus strength, they’ve resolved longstanding debates.
Distinguishing between direct and indirect sets appears essential for predicting adaptations to a given resistance training protocol.
Future research can build upon this fractional quantification framework, potentially refining volume recommendations for specific muscle groups, experience levels, and training phases.
For now, lifters have actionable evidence: volume drives growth with gradual diminishing returns, while frequency matters far more for strength than size.
All data and supplementary materials from this groundbreaking study are publicly available on the Open Science Framework, allowing coaches and athletes to dive deeper into specific findings relevant to their training.
