How much is enough? The dose–response, finally mapped.

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Training Note — No. 01

Strength & Conditioning

How much is enough?
The dose–response, finally mapped.

A February 2026 meta-regression pooled 67 studies to answer the oldest question in the gym. The headline finding is that more sets keep working — but the more useful finding is that most people have been counting their sets wrong.

Georgetown, Seattle12 min readEvidence-based

Written by the coaching team at Root Strength, Georgetown, with input from the Doctors of Physical Therapy at Root Physical Therapy — our on-site clinic. This note pairs with our clinical piece on readiness versus preparedness: this one is about the dose, that one is about whether you should be adjusting it day to day.

"How many sets should I do?" is the question the fitness industry has argued about for thirty years, largely because the honest answer has always been some version of it depends, and we haven't measured it properly.

In February, a research group at Florida Atlantic University published the most thorough attempt yet to map the actual shape of that relationship. Pelland and colleagues ran a series of meta-regressions across 67 studies and 2,058 participants, looking at how weekly set volume and weekly training frequency relate to gains in muscle size and strength.

The result has one headline and one detail. The headline is the one everyone quoted. The detail is the one that will actually change what you write in your training log.

One

The headline: volume keeps working

Across every model, more weekly sets meant more growth and more strength. In statistical terms the authors reported a 100% posterior probability that the relationship between volume and gains was positive — for hypertrophy and for strength.

The Analysis

Figure 01

67

studies pooled across 2,058 participants, average age 25

100%

posterior probability that gains increase as weekly volume increases — both size and strength

8.1

average weekly sets per muscle in the included studies — the range the models are built on

That third number is the one to hold onto. The average weekly volume across the included research was around eight sets per muscle, which means the curve is well-mapped at low-to-moderate volumes and increasingly speculative above that. The models say more is better across the range that was studied — not that there's no ceiling anywhere.

Two

The detail: you've been counting wrong

Here's the part that matters more day to day. Before running any analysis, the authors did something previous reviews hadn't: they classified every single set as either direct or indirect, depending on how specific it was to the muscle or lift being measured.

A set of barbell rows is direct work for your back. It's also doing something for your biceps — but not the same something as a set of curls. So they tested three ways of counting that indirect work: total (count it fully), fractional (count it as half), and direct (don't count it at all). Then they let the data decide.

The fractional method won. The evidence supported counting indirect sets as half a set — which means the field's two most common habits are both wrong in opposite directions.

Counting a Week of Pressing

Figure 02

Work performed

Total

Fractional

Bench press, 4 setsDirect chest work

4.0

4.0

Incline dumbbell press, 3 setsDirect chest work

3.0

3.0

Overhead press, 4 setsIndirect for chest

4.0

2.0

Dips, 3 setsIndirect for chest

3.0

1.5

Weekly chest volume

14.0

10.5

Same week of training, two different numbers. If you've been counting everything, you've been overestimating by roughly a quarter — and wondering why a "sixteen-set" chest week wasn't producing sixteen sets' worth of results. If you've only ever counted direct work, you've been underestimating, and possibly adding volume you were already accumulating.

The argument was never really about how much. It was about what counts.

Three

Frequency is a separate question

The same paper looked at weekly frequency — how many times per week you train a given muscle or lift — and found that volume and frequency have distinct dose–response relationships. They aren't two ways of describing the same variable, which is how they often get discussed.

The practical reading is that frequency is mostly a delivery mechanism. Once you've decided your weekly volume, spreading it across more sessions gives you fresher sets, better technique in the later sets, and more manageable individual sessions. That's a real advantage — but it's an advantage in executing the volume, not a separate stimulus on top of it.

What this means for a normal training week

Set the weekly number first, then divide it. Twelve fractional sets for a muscle group can be two sessions of six or three sessions of four. The research doesn't strongly favour one split, so choose based on what you'll actually do consistently and what leaves technique intact — because a set performed badly at the end of a long session is not the same input as a set performed well.

Four

Volume isn't the only variable — and effort still matters

None of this makes sets a currency you can spend infinitely. A separate line of research has looked at how close to failure each set needs to be, and the answer is reassuring for anyone worried they need to grind every rep.

A meta-analysis of training to failure versus stopping short found no significant difference for strength gains and none overall for hypertrophy. In resistance-trained individuals specifically, there was a small significant advantage to training to failure for muscle growth — but the overall conclusion was that failure isn't required, and that it also doesn't appear to be harmful.

So the picture is: a set has to be hard enough to count, but it doesn't have to be maximal, and past a certain effort threshold the thing that keeps moving the needle is how many of those hard-enough sets you accumulate.

Where the evidence is limited — stated plainly

Three caveats worth carrying. First, the participant pool was young — average age 25 — and roughly 79% male, so extrapolation to older lifters and to women rests on assumption rather than data. Second, because average volumes in the included studies were around eight sets per muscle per week, the models are extrapolating once you get much above that; a positive slope across the studied range is not evidence that thirty sets beats twenty. Third, every one of these participants was recovering from a study protocol, not from a full week of Muay Thai, a job, and a commute — which is exactly the life-load problem that determines whether extra volume becomes adaptation or accumulates as fatigue.

Five

Turning this into a week

Starting points, using fractional counting — indirect work counted as half a set — per muscle group per week.

Weekly Volume by Training Age

Figure 03

I

New to lifting

You will respond to almost anything, so the constraint is tissue tolerance rather than stimulus. Start low and add slowly — the connective tissue that has to survive this adapts considerably slower than your muscles do. Spend the first months building technique you can still execute in a fatigued set.6–10 fractional sets · 2× per week

II

A year or two in

The zone the research maps best, and where most people in our gym sit. If progress has stalled here, recount your sets fractionally before adding any — a fair number of people discover they're doing less than they thought, and a fair number discover they're doing more.10–16 fractional sets · 2–3× per week

III

Experienced and specialising

Higher volumes appear to keep paying, but this is where the models start extrapolating and where individual recovery capacity becomes the binding constraint. Raise volume on one or two priority muscle groups, not everything at once, and hold the rest.16+ fractional sets on priorities · 3× per week

IV

Training a sport alongside lifting

Your Muay Thai, running or climbing is already producing load, and much of it is indirect work by any honest accounting. Lifting volume here should be the amount that supports the sport, not the amount that maximises hypertrophy in isolation — which is a genuinely different number.8–12 fractional sets · 2× per week

Add volume the way you'd add weight: gradually, from a known starting point, one variable at a time. Jumping from eight sets to twenty because a meta-analysis said more is better is how you generate the exact fatigue accumulation that stalls progress.

The practical takeaway

Count fractionally, write it down, and change one thing at a time. The single most useful action from this paper isn't adding sets — it's finding out how many you're actually doing. Most people have never counted properly, which means they've been adjusting a number they couldn't see. Get an accurate baseline first; the decision about whether to raise it is much easier once you have one.

Six

The bottom line

More sets produce more muscle and more strength, across the range of volumes the research has actually studied. Frequency is how you deliver that volume rather than a separate lever. Effort has to be sufficient but doesn't have to be maximal. And indirect work counts — at about half.

The unglamorous conclusion is the same one that shows up everywhere in training science: the people who progress aren't the ones who found the optimal number. They're the ones who know what number they're currently doing, and change it deliberately.

The Short Version

• More weekly sets means more size and strength — 100% posterior probability of a positive relationship across 67 studies and 2,058 participants.
• Count indirect work as half a set. The "fractional" method had the strongest evidentiary support in the analysis.
• The research averages about eight sets per muscle per week, so the curve is well-mapped at moderate volumes and extrapolating above them.
• Volume and frequency behave differently. Set the weekly total, then divide it across sessions you can execute well.
• Training to failure isn't required for strength or, overall, for size — though trained lifters saw a small hypertrophy advantage from it.
• Participants were young and mostly male. Extrapolation beyond that is assumption, not evidence.
• Get an accurate baseline before adding anything. Most people are adjusting a number they've never actually measured.

This article provides general educational information about training and is not medical advice. If you have a current injury, a medical condition, or pain that changes with training, speak with a qualified clinician before altering your programme.

Build the plan, then the numbers.

Root Strength Georgetown — a full training floor, a 12-person cedar sauna, and a physical therapy clinic on-site, so programming and rehab are the same conversation instead of two separate ones.

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Sources

1. Pelland JC, Remmert JF, Robinson ZP, Hinson SR, Zourdos MC. The resistance training dose response: meta-regressions exploring the effects of weekly volume and frequency on muscle hypertrophy and strength gains. Sports Medicine. 2026;56(2):481–505.
2. Grgic J, Schoenfeld BJ, Orazem J, Sabol F. Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy: a systematic review and meta-analysis. Journal of Sport and Health Science. 2022;11(2):202–211.
3. Robinson ZP, Pelland JC, Remmert JF, et al. Exploring the dose–response relationship between estimated resistance training proximity to failure, strength gain, and muscle hypertrophy: a series of meta-regressions. Sports Medicine. 2024.
4. Rogerson D, Nolan D, Korakakis PA, et al. Deloading practices in strength and physique sports: a cross-sectional survey. Sports Medicine — Open. 2024;10:26.
5. Kruczek K, Rebelo A, Gabbett T, Nowak M. The readiness–preparedness bias: recalibrating monitoring logic. Frontiers in Physiology. 2026;17:1855985.