The training variables, with numbers
Volume, load, proximity to failure, frequency, rest, range of motion and tempo: what the evidence says about each, and what range to use.
A program is a combination of seven variables. Almost every argument about training is an argument about one of them, badly isolated from the rest. Here is each one with its working range and the evidence behind it.
| Variable | Working range | How much it matters |
|---|---|---|
| Volume (sets/week/muscle) | 10–20 direct sets | A lot: it is the engine of hypertrophy |
| Load | 30–85% 1RM (6–20 reps) for size; >80% for strength | Depends on the goal |
| Proximity to failure | 0–3 RIR on most sets | A lot with light loads; less with heavy ones |
| Frequency | 2× per muscle per week | Little for size, some for strength |
| Rest between sets | 90 s – 3 min | Moderate: under 60 s costs you |
| Range of motion | The largest your technique allows | Moderate, favouring the long range |
| Tempo | 1–3 s on the eccentric | Little, unless the tempo is very slow |
1. Volume: the engine
The volume–outcome relationship rises, but with diminishing returns
The Pelland meta-regression (67 studies, 2,058 subjects) estimates with 100% posterior probability that size and strength gains increase with weekly volume, and that both models show diminishing returns, far more marked for strength. It also concludes that separating direct from indirect sets is essential to predicting adaptation.
- Direct set: the muscle is the target of the exercise (a curl for biceps).
- Indirect or fractional set: the muscle takes part but is not the target (biceps in a row). Count it as half a set.
- Start at 10 weekly direct sets per muscle group and add two at a time, only if you recover and keep progressing.
Volume has a practical ceiling
The ceiling is not set by physiology but by your recovery, your time and your joints. Twenty well-executed sets beat thirty done at half effort.
2. Load: what weight to use
| Goal | Load | Reps | Sets per exercise |
|---|---|---|---|
| Maximal strength | ≥80% 1RM | 1–6 | 2–5 |
| Hypertrophy | 60–80% 1RM (and 30–60% taken close to failure) | 6–20 | 2–4 |
| Muscular endurance | <60% 1RM | 15–30+ | 2–3 |
| Power | 30–70% 1RM, explosive concentric | 3–6 | 3–5 |
The important nuance: the “hypertrophy range” of 8–12 reps is a convenient convention, not a law. Sets of 5 and sets of 25 both build muscle if the effort is there; what changes is the accumulated fatigue and how long it takes you.
3. Proximity to failure
Training to failure adds little over stopping close to it
The systematic review with meta-analysis by Refalo and colleagues found a trivial advantage for failure over non-failure for hypertrophy (ES ≈ 0.19). Later meta-regressions describe a small advantage as you approach failure within roughly 0–5 RIR, dropping off more sharply above 5 RIR, while strength stays similar across a wide RIR range.
- Work most sets at 1–3 RIR. It is the best stimulus-to-fatigue trade.
- Save failure for isolation work or machines, where failing is safe.
- With very light loads (≈30% 1RM), failure is needed to recruit everything.
- On heavy compounds, failing costs days of recovery and wrecks the technique of the sets that follow.
4. Frequency
With volume matched, frequency barely changes hypertrophy
Volume-matched frequency meta-analyses show no relevant effect on hypertrophy; the dose–response meta-regression reaches the same conclusion for size, but does find more strength at higher frequencies (with diminishing returns). In other words: frequency is mostly a tool for spreading out volume and practising the movement.
Rule of thumb: twice a week per muscle group. Not because the muscle “switches off” after 48 hours, but because splitting 16 sets across two days lets you execute them better than doing them all in one go.
5. Rest between sets
Under 60 seconds costs you; over 90 adds little
The Bayesian meta-analysis by Longo and colleagues finds a small hypertrophic benefit to resting longer than 60 seconds, and no appreciable difference once you go past 90 seconds.
- Isolation
- 60–90 s
- Moderate compounds
- 2 min
- Heavy compounds / strength
- 3–5 min
Here neural recovery decides, not the clock.
6. Range of motion
Training at long muscle lengths has an advantage
Reviews of partial-range work compare training at long versus short muscle lengths and find greater hypertrophy at long lengths. Against full range, lengthened partials produce similar adaptations, not superior ones. The operational recommendation is still to use the largest range your technique allows without pain.
7. Tempo and exercise order
- Tempo: control the lowering (1–3 s) and lift without braking. Very slow tempos (>4 s) cut the volume you can do without adding anything.
- Order: whatever comes first gets executed best. Put the most demanding exercises, or the muscle you want to prioritise, at the start; order affects the reps you get per set and therefore your effective volume.
Exercise order shapes session performance
The review by Simão and colleagues concludes that order affects both acute responses and chronic adaptations: you get more reps — and therefore more volume — on the exercises placed early in the session.
If you only take one thing
- Volume: 10–20 direct sets per muscle per week, split across 2 days.
- Effort: 1–3 reps in reserve on almost everything.
- Rest: 2 minutes by default; never under 60 seconds.
- Range: the largest you can control, looking after the stretched position.
- Load: whatever puts you in that rep range at that effort.
Sources for this chapter
- [1]Pelland JC, Robinson ZP, Remmert JF, et al. (2025). The Resistance Training Dose Response: Meta-Regressions Exploring the Effects of Weekly Volume and Frequency on Muscle Hypertrophy and Strength Gains. Sports Medicine. meta-analysis
- [2]Schoenfeld BJ, Grgic J, Van Every DW, Plotkin DL (2021). Loading Recommendations for Muscle Strength, Hypertrophy, and Local Endurance: A Re-Examination of the Repetition Continuum. Sports (Basel). review
- [3]Refalo MC, Helms ER, Trexler ET, Hamilton DL, Fyfe JJ (2023). Influence of Resistance Training Proximity-to-Failure on Skeletal Muscle Hypertrophy: A Systematic Review with Meta-analysis. Sports Medicine. meta-analysis
- [4]Robinson ZP, Pelland JC, Remmert JF, et al. (2024). Exploring the Dose-Response Relationship Between Estimated Resistance Training Proximity to Failure, Strength Gain, and Muscle Hypertrophy: A Series of Meta-Regressions. Sports Medicine. meta-analysis
- [5]Schoenfeld BJ, Grgic J, Krieger J (2019). How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of studies examining the effects of resistance training frequency. Journal of Sports Sciences. meta-analysis
- [6]Longo AR, Silva-Batista C, Pedroso K, et al. (2024). Give it a rest: a systematic review with Bayesian meta-analysis on the effect of inter-set rest interval duration on muscle hypertrophy. Frontiers in Sports and Active Living. meta-analysis
- [7]Ulster University (revisión sistemática y meta-análisis) (2025). Muscle hypertrophy from partial repetition at long vs. short muscle length: a systematic review and meta-analysis. Ulster University Research Portal. meta-analysis
- [8]Larsen S, Swinton P, Sandberg NØ, et al. (2025). Lengthened partial repetitions elicit similar muscular adaptations as full range of motion repetitions during resistance training in trained individuals. PubMed. trial
- [9]Simão R, de Salles BF, Figueiredo T, Dias I, Willardson JM (2012). Exercise order in resistance training. Sports Medicine. review