The Study
Resistance training frequency and skeletal muscle hypertrophy: A review of available evidence.
This study is like a teacher reading a bunch of other science reports and telling you what they found about how often you should exercise to build muscle. It doesn't do the exercise experiments itself, so it can only tell you what other researchers have seen, not prove exactly why or how it happens. You can trust it as a helpful summary, but it doesn't give you a final, proven answer.
Analysis score
Maximum 5 for a narrative review.
Where the score came from
This review looked at existing research to see if how often you work out a muscle group changes how much muscle you grow, as long as you do the same total amount of work each week.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 51 / 100
Quality score
Systematic reviews and meta-analyses of cohort studies. They sit above a single cohort study but below a single randomized trial, because the underlying evidence is still observational.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes, this means you can train each muscle group just once a week and still build the same amount of muscle as training it more frequently, provided you complete the same total weekly workouts.
- 2Studies using accurate muscle measurements found no difference in muscle growth between training once, twice, or three times per week.
- 3Measurements based on limb size were found to be unreliable.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of science and medicine in sport
Year
2019
Authors
J. Grgic, B. Schoenfeld, C. Latella
Related Content
Claims (4)
If you do the same total amount of weightlifting work each week, doing it all in one session will build your muscles just as much as spreading those workouts across multiple days.
If you lift the same total amount of weight each week, it doesn't matter if you do it all in one day or spread it out over two or three days—you'll build the same amount of muscle. Your total weekly effort matters more than how you split it up.
If you do the same total amount of weightlifting each week, it doesn't matter if you split it up over several days or do it all at once—your muscles will grow the same amount. Objective measurements show that how often you train doesn't change the results as long as the total work stays the same.
Measuring your arm or leg size with a tape measure isn't a great way to tell if you're actually building muscle. Since the tape can't tell the difference between muscle, fat, and water, changes in size might just be from gaining fat or holding water instead of real muscle growth.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.