Reps, Sets and Frequency for Muscle Growth: What the Research Says

Walk into any gym and you will hear confident rules: eight to twelve reps for size, never more than three sets, train each muscle once a week. Researchers have now pooled dozens of training studies, and the picture is more relaxed, and more useful, than the gym folklore.

This guide covers reps, sets and frequency, plus rest times and progressive overload. For each you get what the meta-analyses found and what it means for your next week of training, with three sample plans at the end. Everything here is a research finding, not a guarantee: results vary from person to person.

Reps: is there a magic hypertrophy zone?

The classic teaching is the repetition continuum: 1 to 5 reps for strength, 8 to 12 for size, 15 or more for endurance. The 2009 position stand of the American College of Sports Medicine (ACSM) still emphasises the 6 to 12 repetition maximum zone for hypertrophy.

Newer research loosens this up. A 2017 meta-analysis of 21 studies compared low-load (60% of one-rep max or less) with high-load training (above 60%), all sets taken to momentary failure. Heavy loads produced greater gains in one-rep-max strength, while muscle growth was similar (Schoenfeld et al., 2017). In a 12-week trial, 49 resistance-trained men trained to failure with 8 to 12 or 20 to 25 reps per set; lean mass and muscle fibre size rose similarly in both groups (Morton et al., 2016).

A 2021 review concluded that similar whole-muscle growth is possible across a wide spectrum of loads from about 30% of one-rep max and up, so there is no single ideal hypertrophy zone. It also names trade-offs: light sets need many more reps and feel harder, while very heavy training needs more sets to match and loads the joints more. Moderate loads are a practical sweet spot (Schoenfeld et al., 2021).

How close to failure should you train?

Most studies above had people train every set to failure, so effort matters. A 2023 meta-analysis of 15 studies compared training to failure with stopping short. Across all definitions of set failure the advantage was trivial (effect size 0.19), and for momentary muscular failure versus non-failure there was no advantage (effect size 0.12, interval -0.13 to 0.37). The authors found no evidence that failure is superior and noted the relationship may not be linear (Refalo et al., 2023).

Sets: how many per muscle per week?

Sets are the most consistent lever in the research. A 2017 meta-regression of 15 studies found that each additional weekly set per muscle was associated with about 0.37% extra growth, and higher-volume groups gained on average 3.9% more than lower-volume groups. Fewer than 5, 5 to 9 and 10 or more weekly sets gave only a trend (P = 0.074). The authors describe a graded dose-response relationship (Schoenfeld, Ogborn and Krieger, 2017).

Is there a ceiling? A 2022 review of trained men aged 18 to 35 compared 12 to 20 weekly sets per muscle with more than 20. There was no difference for the quadriceps or biceps, while more sets did better for the triceps. The authors suggest 12 to 20 sets per muscle as a reasonable standard for this group (Baz-Valle et al., 2022), based on seven studies, so treat it as a starting range.

Frequency: how often should you train each muscle?

Frequency can mean sessions per week, or how many times per week you train a given muscle. The research question is mostly the second.

The 2016 meta-analysis of 10 studies found larger hypertrophy effects for higher frequencies (0.49 versus 0.30). On a volume-equated basis, training a muscle twice a week beat once a week, and the authors inferred major muscles should be trained at least twice weekly (Schoenfeld et al., 2016).

The 2019 update, with 25 studies, shifted the emphasis. On a volume-equated basis there was no significant difference between frequencies, including in trained people. The authors concluded that frequency does not meaningfully affect hypertrophy when volume is equated, so you can choose based on preference (Schoenfeld et al., 2019). For strength too, the benefit of higher frequency disappeared when volume was equated (Grgic et al., 2018).

So frequency is mainly a way to spread your weekly sets, which keeps sessions shorter and sets sharper (a practical argument, not a study result). The ACSM recommends 2 to 3 sessions a week for novices, 3 to 4 for intermediates and 4 to 5 for advanced lifters (ACSM, 2009).

Rest between sets

In an eight-week study, 21 trained men did three full-body workouts a week with either 1 or 3 minutes of rest. The 3-minute group gained more squat and bench press strength and more thigh muscle thickness (Schoenfeld et al., 2016). A 2024 Bayesian meta-analysis of 9 studies found a small hypertrophic benefit to resting more than 60 seconds and no appreciable difference beyond 90 seconds (Singer et al., 2024). For strength, trained lifters seem to need more than 2 minutes (Grgic et al., 2018).

Progressive overload: how to keep growing

Muscles adapt to what you ask of them, so the demand has to rise. You can add load or add reps. In an eight-week trial, 43 resistance-trained people trained their legs twice a week, one group adding load at constant reps and the other adding reps at constant load. Differences were small and of questionable practical significance, and the authors concluded both are viable (Plotkin et al., 2022). The ACSM suggests raising load by 2 to 10% once you can do one to two reps over your target (ACSM, 2009).

Sample weekly plans

Sets are hard sets, rep ranges are approximate and exercises can be swapped. Totals count only sets that directly train a muscle.

Full body, 3 days a week (beginners)

About 9 weekly sets each for quads, chest and back, and 6 each for hamstrings, side delts, biceps and triceps.

Upper/lower, 4 days a week

About 6 weekly sets for chest, 10 for back, 8 for quads, 7 for hamstrings, 6 for calves and 4 each for biceps and triceps. Every muscle twice a week.

Push/pull/legs, 6 days a week (advanced, high commitment)

About 10 weekly sets for chest, 12 for back, 10 each for quads and hamstrings, and 6 each for side delts, biceps, triceps and calves. Run it only three days a week and each muscle is trained once, less effective than twice in the 2016 meta-analysis.

Beginners versus advanced lifters

Session counts come from the ACSM (novices untrained, intermediates about 6 months of consistent training, advanced lifters years). The set and rep rows are our practical starting points, not study results.

Fuelling the work

Training provides the stimulus and food supports it. A protein shake is one convenient way to add protein to your day. Our RAW Whey Concentrate comes in Dark Cookies and Sweet Chocolate. New to protein? Read our Protein 101 guide.

Creatine is the other well-studied option for hard, repeated efforts, and we cover the details in our creatine guide. Mixing is easy in the Shaker V2.

FAQ

The bottom line

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