Not much, in the one trial that tested it directly: trained lifters who jumped one leg to 120% more weekly sets overnight grew that leg about as much as the other leg, which got only 20% more5. The big jump bought no extra growth, and it did not blunt growth either.
That answer only covers eight weeks, one muscle and people who already lift. Below: how the test worked, what else the volume research says, and where "more" stops paying.
What was studied
Training volume here means the number of hard sets a muscle gets per week. Habitual volume is what someone was already doing before a study starts.
A Brazilian team recruited 25 resistance-trained men and women aged 18 to 355. The preprint of the same study gives the detail: 18 men and 7 women, about four years of training, doing on average 14.9 sets a week for the thighs before the study6. Each person's two legs were randomised. One leg stayed close to habit with a 20% increase. The other jumped by 120% from the first week and stayed there for eight weeks.
Both legs trained twice a week on the leg press and leg extension, every set to failure (until no further rep was possible) in the 9–12 rep range, under supervision6. Growth was measured as cross-sectional area of the outer thigh muscle (the vastus lateralis) on ultrasound, by assessors who did not know which leg was which. Small muscle samples (biopsies) were taken to measure fibre size, muscle stem cells and molecular signals of building and breakdown5.
| What | +20% leg | +120% leg |
|---|---|---|
| Habitual thigh sets per week | 14.9 (same person) | 14.9 (same person) |
| Sets per week actually done | 18.0 | 32.8 |
| Sessions | 16 over 8 weeks | 16 over 8 weeks |
| Sets | to failure, 9–12 reps | to failure, 9–12 reps |
Weekly thigh sets: habit vs each leg in the trial · sets/week
In plain terms: the same person, the same weeks, the same meals; one leg did about twice the sets of the other.
What the study found
Both legs grew. Muscle cross-sectional area rose over time on both legs6. There was no protocol-by-time interaction, the statistical test for whether one leg grew faster than the other.
The big jump did not add growth. The journal version concludes that a large, abrupt increase "did not enhance muscle hypertrophy compared with a modest increase"5. In the preprint, the difference between legs in growth was 2.7%, which the authors called "small and close to" the ultrasound method's measurement error of 2.3%6. The standardised effect was −0.36 with a 95% confidence interval of −1.35 to 0.64. An interval that wide, crossing zero, is compatible with a small advantage for either leg or none.
It did not blunt growth, either. The authors "found no evidence that the larger volume progression attenuated adaptation"5. Fibre size, stem-cell and nuclear content, and the building and breakdown signals did not differ significantly between legs. The preprint's summary: trained muscle "can accommodate a large abrupt increase in weekly set volume without detectable morphological impairment"6.
In plain terms: 33 sets a week grew the thigh about as much as 18. The extra sets were not rewarded, and not punished, in this trial.
Does that fit the rest of the volume research?
Mostly, with a twist. Pooled across 67 studies and 2,058 participants, growth rises with weekly sets, with diminishing returns4. So more volume helps on average, but each extra set adds less.
Where people start matters. In a 2019 trial, 34 trained men did one, three or five sets per exercise, three times a week, for eight weeks1. Growth favoured the higher volumes at several sites, while strength gains were similar across all three. That trial set volumes in absolute terms, not relative to each person's history.
Trials anchored to habitual volume look different. In 2025, trained men either kept their previous weekly sets for the legs, or raised them by 30% or 60%, for eight weeks3. All groups grew. Thigh muscle thickness rose 1.07 cm with no change, 0.76 cm with +30% and 0.70 cm with +60%, and the authors reported no group differences in muscle size. The group that kept its volume had the greatest overall squat 1RM.
Thigh muscle thickness gain by change in weekly sets, trained men · cm
A 2024 trial added sets gradually instead: four or six extra sets every two weeks over 12 weeks, against a constant-volume group2. Strength rose more with more sets. Growth showed no significant difference between groups; the authors saw a possible small benefit that appeared to plateau at the higher volumes, with limited certainty.
In plain terms: in already-trained people, big increases above what they were doing have not bought clear extra growth in these trials.
What this does and does not mean
It does not mean volume is irrelevant. Across the literature, more sets tend to mean more growth up to a point, especially for people who start low (see how many sets a beginner should do).
It does not show that doubling is harmless for everyone. Eight weeks on two thigh exercises is a narrow window. The preprint reports that three people withdrew during follow-up because of persistent muscle or joint pain; it does not say which leg's protocol was involved6. Fatigue and recovery across a whole programme were not measured (see signs of accumulated training fatigue).
What it does suggest: for trained lifters already doing moderate volume, a large step up may cost a lot of extra time for little measurable return in the short term. For how weekly volume targets are usually set, see how many sets per muscle group per week.
What the studies found
| Study | Who was studied | Key result | Year |
|---|---|---|---|
| Schoenfeld et al., *Med Sci Sports Exerc*1 | 34 trained men, 1, 3 or 5 sets per exercise, 8 weeks | Growth favoured higher volumes at several sites; strength similar | 2019 |
| Enes et al., *Med Sci Sports Exerc*2 | 31 trained men, sets added every 2 weeks, 12 weeks | More strength with more sets; no significant growth difference | 2024 |
| Barsuhn et al., *J Appl Physiol*3 | 29 trained men, +0%, +30% or +60% sets, 8 weeks | No group differences in muscle size | 2025 |
| Pelland et al., *Sports Med*4 | 67 studies, 2,058 participants | Growth rises with volume, with diminishing returns | 2026 |
| Camargo et al., *J Appl Physiol*5 | 25 trained adults, +120% vs +20% by leg, 8 weeks | No extra growth from the big jump; no blunting; signals similar | 2026 |
Limits worth knowing
- One trial, 25 people. The direct test is small; it can miss a modest difference either way.
- Eight weeks, one muscle. Only the outer thigh was scanned, after leg press and leg extension.
- Trained, not elite or new. The authors note the results apply to recreationally trained people.
- Diet recorded, not controlled. The authors list this as their first limitation6.
- Preprint vs journal. The journal paper was read as an abstract (its stored abstract is cut mid-sentence); the detail here comes from the February 2026 preprint, read in full. The peer-reviewed version may differ in detail.
- Abstract only. The 2019, 2024, 2025 and 2026 comparison studies were read as abstracts.
Latest research
The newest study is the Camargo trial itself, published in the *Journal of Applied Physiology* in August 20265. It is the first we found that anchored both doses to each person's habitual volume and compared them within the same person. Its result sits alongside the 2026 dose-response meta-regressions4: volume helps, the returns shrink, and in trained lifters a sudden large jump did not show a measurable payoff over eight weeks.
The short version
- In trained lifters, a leg jumped to +120% weekly sets grew about as much as a leg given +20%.
- The big jump did not measurably blunt growth or change muscle-building signals.
- Another trial in trained men found no significant growth difference between +30% or +60% sets and keeping volume steady.
- Across all studies, volume helps with diminishing returns; the direct test is short and small.
Educational overview only — not medical advice.
