Effects of Resistance Training Frequency on Measures of Muscle Hypertrophy: A Systematic Review and Meta-Analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of experimental trials
PubMed 27102172 · doi:10.1007/s40279-016-0543-8
What was done
A systematic review and meta-analysis evaluated experimental trials in healthy humans without chronic disease or injury directly comparing different weekly resistance training frequencies with dynamic concentric and eccentric exercise lasting at least 4 weeks. Outcomes were required to measure morphological changes using biopsy, imaging, circumference, or densitometry. Ten studies met all inclusion criteria.
What was found
Using binary frequency as a predictor, higher weekly training frequency produced a significantly larger hypertrophy effect size than lower frequency (0.49 ± 0.08 vs. 0.30 ± 0.07; P = 0.002). When volume was equated across studies comparing 1 to 3 days per week per muscle group, training twice per week promoted superior muscle growth compared to once per week. Data were insufficient to determine whether training a muscle group three times per week is superior to twice per week, or to evaluate overall session frequency when per-muscle-group frequency was matched.
Why it matters
This review provides quantitative evidence that distributing resistance training volume to train muscle groups at least twice weekly enhances hypertrophy compared to once-weekly regimens.
Limits
The meta-analysis included only 10 studies. Sample sizes were inadequate to evaluate training session frequency independent of muscle-group frequency or to resolve whether 3 days per week yields additional hypertrophy compared to 2 days per week.
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.