How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of resistance-training frequency (frequency as a vehicle for volume)
Key Findings
Systematic search (PubMed/MEDLINE, Scopus, SPORTDiscus); 25 studies met inclusion.
Volume-equated: no significant difference in hypertrophy between higher and lower weekly frequency.
The null held across all categories examined: direct measures of muscle growth, resistance-trained participants, and upper- vs lower-body training.
Non-volume-equated studies: meta-regression showed a significant effect favouring higher frequencies, but the difference between 1 and 3+ days per week was modest — i.e. when higher frequency "works", it is because it carried more total volume.
Authors' conclusion: strong evidence that frequency does not significantly or meaningfully affect hypertrophy when volume is equated; for a given volume, choose weekly frequency per muscle group by personal preference.
Practical Application
Meta-analysis of 25 studies: with weekly volume equated, training a muscle more often per week did not produce more hypertrophy — the null held for direct growth measures, trained lifters, and upper and lower body alike; only when higher frequency also meant more total volume did it help, and then modestly. Frequency is how you distribute the sets, not a growth stimulus in itself.
Masters/hybrid: distribute the needed volume (REF-513) across 2-3 sessions if that fits recovery and the endurance calendar better; or run 1 dense session if time is short — at equal volume the meta-analysis expects the same result.
Endurance athletes: the flexibility is the point — place strength sessions where they least interfere with key endurance sessions (REF-512) rather than chasing a frequency target.
Hybrid/HYROX prep: 2× shorter strength blocks between running/station sessions is a legitimate way to deliver the same weekly volume.
Limitations
Volume-equated design: in practice higher frequency often = higher total volume (then frequency "works" via volume — the non-equated meta-regression shows this, modestly)
Mostly young/trained samples; masters may benefit from higher frequency with less load per session (recovery) — inference, not tested here
Outcome is hypertrophy, not strength or endurance-sport performance
How this entry was checked and changed
Content correction 2026-09-27
Sport running/strength -> strength (the included studies are resistance-training hypertrophy trials).
Added: 25 studies; null across direct measures / trained / upper vs lower body; non-volume-equated meta-regression favours higher frequency but 1 vs 3+ days differs only modestly.
Lead bullet now the pooled finding; "1× vs 2× vs 3×/week" replaced by the abstract's 1 vs 3+ days framing.