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.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of experimental trials.
PubMed 30558493 · doi:10.1080/02640414.2018.1555906
What was done
A systematic review and meta-analysis of 25 experimental studies identified via PubMed/MEDLINE, Scopus, and SPORTDiscus to evaluate the effects of weekly resistance training frequency on muscle hypertrophy. Subgroup and meta-regression analyses evaluated volume-equated versus non-volume-equated designs, direct measures of muscle growth, participant training status (resistance-trained), and body region (upper vs. lower body).
What was found
When training volume was equated, higher versus lower frequencies showed no significant difference in muscle hypertrophy. No significant differences were observed across frequency categories for direct measures of growth, resistance-trained individuals, or upper versus lower body musculature. In non-volume-equated studies, meta-regression showed a significant effect favoring higher training frequencies, though the difference in magnitude between 1 and 3+ days per week was modest. Exact numerical effect sizes, variance estimates, and p-values were not reported in the abstract.
Why it matters
Weekly resistance training frequency does not meaningfully influence muscle hypertrophy when total volume is matched. Lifters can distribute their weekly sets across preferred training splits without compromising muscle growth.
Limits
The abstract does not provide exact numerical effect sizes, confidence intervals, total participant numbers, sex/age demographics, or risk-of-bias assessments. Non-volume-equated findings are confounded by total training volume.
Cited by
- context Scientific evidence indicates that training a muscle three times per week may be superior for maximizing muscle gains compared to lower frequencies.
- supports There is little evidence in the scientific literature demonstrating that training a muscle group three times per week produces superior muscle growth compared to twice per week.
- supports Performing whole-body resistance training 2 days per week is sufficient to achieve musculoskeletal maintenance and benefits.