Schoenfeld Sets Per Week: 2017 Dose-Response and Junk Sets

How many sets per week did Schoenfeld's research find for hypertrophy? More is better up to at least 10 sets per muscle: the 2017 meta-analysis linked each additional weekly set to about 0.37% more growth, and the 2019 trial grew more muscle on about 15 weekly sets than on 3 or 9, without extra strength.^[1][2] This article walks through what those studies and the higher-volume trials found, and where the junk-volume boundary plausibly sits, reporting the published findings rather than invented precision.

The framework: what counts as a "set"

Set-volume math is sensitive to what counts. The volume studies count working sets, which in most included trials were taken to or close to failure; warm-ups do not count. Two refinements since 2017 sharpen the definition:

• Indirect sets count as half. Pelland 2026's meta-regressions fitted best when a set that only works a muscle indirectly (a row for the biceps) counted as 0.5.^[5]
• Proximity to failure matters for size. Robinson 2024 found hypertrophy rose as sets were taken closer to failure, while strength was much less sensitive to it.^[6]

This matters because lifters who count every set ("I did 25 sets for chest!") routinely double-count and over-state their actual hypertrophy-relevant working volume.

The Schoenfeld 2017 meta-analysis

The 2017 paper analysed 34 treatment groups drawn from 15 studies, regressing muscle-size change against weekly working-set volume. Its headline result was a significant, graded dose-response: more weekly sets produced greater hypertrophy (P = 0.002), with the relationship described as roughly linear across the studied range. The authors reported that each additional weekly set raised the effect size by 0.023, about 0.37% more growth per set. Split into fewer than 5, 5-9 and 10+ weekly sets per muscle, the 10+ group trended highest (P = 0.074), which is where the common "at least 10 sets" advice comes from.^[1]

Two cautions the authors themselves stressed: the dataset was heterogeneous, and few of the pooled trials pushed weekly volume far above ~20 sets per muscle, so the upper end of the curve is poorly characterised. The meta-analysis establishes the direction and rough threshold, not a precise per-volume-bracket percentage table.^[1]

The Schoenfeld 2019 trial

The 2019 trial ("Resistance Training Volume Enhances Muscle Hypertrophy but Not Strength in Trained Men") randomised 34 resistance-trained men to three volume conditions and trained them three times a week for eight weeks:

Group              Per session    Weekly sets per muscle
─────────────────────────────────────────────────────────
 Low volume        1 set/exercise        ~3
 Moderate volume   3 sets/exercise       ~9
 High volume       5 sets/exercise      ~15

The published result: all groups increased strength and endurance with no significant between-group differences, while hypertrophy showed significant advantages for the higher-volume conditions at several measured sites (elbow flexors, mid-thigh, and lateral thigh). In other words, extra weekly sets bought additional muscle size but not additional strength over this eight-week block.^[2]

That decoupling — more volume helping size but not strength — is the operational seed of the "junk volume" idea: past the point where strength stops responding, additional sets are working only the hypertrophy channel, at a recovery cost.

Where the junk-volume threshold sits

Pushing the volume question higher, the Heaselgrave 2019 trial randomised 49 trained men to 9, 18, or 27 weekly sets of biceps work for six weeks. Biceps thickness rose 4.3%, 9.5% and 5.4% respectively; the differences were not statistically significant, but effect sizes favoured the 18- and 27-set groups over 9 sets.^[3] The 27-set group did not beat the 18-set group, which fits a curve that flattens somewhere past 20 sets. The larger Pelland 2026 analysis likewise found diminishing returns rather than a hard ceiling.^[5] The exact flattening point varies by individual and muscle group, so the honest reading is a region, not a single number:

Sets/muscle/wk    Practical read
─────────────────────────────────────────────────────────────────────
  under 10        likely sub-optimal for hypertrophy in trained lifters
  10 - 20         the commonly cited productive band
  20 - 27         growth can continue, but per-set returns diminish
  above ~27       little supporting data; recovery cost dominates

Below roughly 10 sets, hypertrophy is generally sub-optimal for trained men; in the 10–20 band the dose-response is reliable; above it the marginal gain shrinks and recovery and joint stress rise. The published trials do not support precise per-set percentage yields beyond this qualitative shape.^[3][5]

The strength-vs-hypertrophy divergence

The 2019 trial's most notable finding was the divergence between strength and hypertrophy: across its 3-to-15 weekly-set range, strength gains were statistically indistinguishable between groups while hypertrophy favoured higher volume. The higher-volume work kept feeding the size channel after strength had stopped responding. The mechanism is the published difference between neural and structural adaptation:

• Strength adaptation is primarily neural (motor unit recruitment, rate coding, intermuscular coordination). The neural system saturates at modest volume because the inputs are skill-rep-based, not work-volume-based.
• Hypertrophy adaptation is structural (protein turnover, fiber cross-section growth) and keeps responding to additional volume longer. Pelland 2026 found diminishing returns far more pronounced for strength than for size,^[5] although a separate meta-analysis did find higher weekly set volumes produced modestly more strength than lower ones (effect size difference 0.18).^[4]

Practical consequence: powerlifters and strength athletes can stay well below 15 weekly sets per muscle without losing strength outcomes. Bodybuilders and physique athletes benefit from pushing toward 20+ weekly sets where the marginal hypertrophy gain still exists despite no strength upside.

Bottom line: where to set weekly volume

1. Strength-focused lifters: 8–12 weekly sets per muscle. Plateau region for strength; additional volume costs recovery without benefit.
2. Balanced strength + hypertrophy: 12–18 weekly sets per muscle. Hits the productive band on both curves.
3. Hypertrophy-focused lifters: 16–22 weekly sets per muscle. Captures the hypertrophy-specific gains while staying inside sustainable recovery.
4. Advanced hypertrophy specialists in short blocks: 22–28 weekly sets per muscle, 4–6 week blocks with planned deload. Pushes the curve into the diminishing-returns zone for short-block productivity.
5. Above ~27 weekly sets: Sparsely studied; likely junk-volume territory for most trained lifters. The Heaselgrave trial's 27-set arm grew less than its 18-set arm (5.4% vs 9.5%, not significant), and such volumes are hard to recover from over multi-month blocks.^[3]

Where the methodology bends

Genetic variation

The dose-response curves above represent population averages, and the standard deviations in these trials are as large as the mean gains (Heaselgrave's 18-set group grew 9.5% ± 11.8%).^[3] Some lifters keep growing at volumes where others stall. The practical approach is to start in the 10-20 set range and adjust on 8-12 weeks of your own tracking.

Compound vs isolation volume

Set-per-muscle math counts both compound and isolation sets that train the muscle. Pelland 2026 found the best fit when indirect work counted as half a set: a squat is a full quad set and roughly half a set for muscles it trains less directly, and a leg extension is a full quad set.^[5] Lifters who run heavy compound programmes accumulate working sets per muscle faster than the simple session count suggests.

Untrained subjects

The 2019 trials recruited trained men. Untrained people grow on lower volumes, and in Pelland 2026 training status was one of the factors the models adjusted for.^[5] The 10-20 set band is a target for trained lifters, not a starting point for novices.

Worked weekly volume by muscle group

A concrete weekly volume plan for an intermediate hypertrophy-focused lifter:

Muscle group      Compound sets    Isolation sets    Total weekly sets
─────────────────────────────────────────────────────────────────────────
Chest             6 (bench)        6 (flyes, cable)   12
Back               8 (rows + pulls) 6 (face pulls)    14
Shoulders         4 (press)         8 (laterals)      12
Biceps            (4 from rows)    8                 12
Triceps           (4 from bench)   8                 12
Quads             6 (squat)        6 (leg ext)        12
Hamstrings        4 (RDL)          6 (curls)         10
Glutes            6 (squat + RDL)  4 (hip thrusts)   10
Calves            -                12                12

Every major muscle group lands in the 10–14 set band, comfortably inside the productive range from the 2017 meta. The structure splits compounds across major movements and adds targeted isolation to fill out volume on the muscles compounds under-stimulate (laterals, biceps, triceps, calves).

Lifters who push for more aggressive hypertrophy can add 2 sets per muscle group across 4–6 week blocks, landing at 16–18 sets per muscle. Above 20 sets per muscle group, watch recovery markers (sleep quality, performance at a fixed effort) and drop back to 12-14 sets every third or fourth week; this is coaching practice rather than a tested protocol.

Cross-checking against related tools

The Junk Volume Detector reads a training log and flags two kinds of set per exercise: sets lighter than 60% of that week's top weight, and sets beyond 12 a week once weekly volume load has failed to grow 2.5% for two weeks running. It is a progression heuristic, not an implementation of the Schoenfeld curve. The Workout Volume Calculator handles the per-week set-counting math. The Progressive Overload Planner sequences volume across multi-week blocks.

Related reading: How Many Sets Per Week for Hypertrophy? for the 2026 dose-response curve turned into weekly set targets, Junk Volume Detector for the per-lifter junk-set diagnostic, Block vs DUP Periodisation for the volume-distribution debate, and Evidence-Based Programming 2026 for the broader framing.

FAQ

If more sets build more muscle, why call high volume "junk"?

Because the marginal cost-benefit flips. In the trials, the highest-volume groups added little or no extra hypertrophy per set and no extra strength,^[2][3] while the recovery demand keeps climbing. The trials lasted 6-8 weeks, so the cost over a full training year is an extrapolation, not a measurement.

How do I count compound exercises in the set total?

Count a compound set as one set for its main movers and half a set for muscles it works indirectly, the method that best fitted Pelland 2026's data.^[5] A row is one back set and half a biceps set. The goal is to land in the productive band, not to optimise to the third decimal.

What if I'm not training to failure?

Most sets in the volume studies were taken to or near failure. Robinson 2024's meta-regressions found hypertrophy increased as sets ended closer to failure, while strength gains were largely unaffected,^[6] so lifters who routinely stop four or more reps short should expect less growth per set than the volume studies imply.

Should I increase volume slowly or jump to the optimal band?

Gradually. No trial has compared ramp rates directly, but adding one or two weekly sets per muscle at a time lets you see whether the extra volume is producing results before you commit to it, and gives sleep, food and joints time to catch up.

References

1. 1 Dose-response relationship between weekly resistance training volume and increases in muscle mass: a systematic review and meta-analysis (Schoenfeld, Ogborn, Krieger) — Journal of Sports Sciences (2017)
2. 2 Resistance training volume enhances muscle hypertrophy but not strength in trained men (Schoenfeld et al.) — Medicine and Science in Sports and Exercise (2019)
3. 3 Dose-response relationship of weekly resistance-training volume and frequency on muscular adaptations in trained men (Heaselgrave et al.) — International Journal of Sports Physiology and Performance (2019)
4. 4 The effect of weekly set volume on strength gain: a meta-analysis (Ralston et al.) — Sports Medicine (2017)
5. 5 The Resistance Training Dose Response: Meta-Regressions Exploring the Effects of Weekly Volume and Frequency on Muscle Hypertrophy and Strength Gains (Pelland, Remmert, Robinson, Hinson, Zourdos) — Sports Medicine (2026)
6. 6 Exploring the Dose-Response Relationship Between Estimated Resistance Training Proximity to Failure, Strength Gain, and Muscle Hypertrophy: A Series of Meta-Regressions (Robinson et al.) — Sports Medicine (2024)