The Study
Muscle Hypertrophy Response Is Affected by Previous Resistance Training Volume in Trained Individuals
This study tried to see if giving people different amounts of weight training made their muscles grow more — and because they randomly picked which leg got which plan, we can guess that the plan caused the difference. But we don’t know if the trainers or testers knew which plan was which, and only 16 people were in the study, so we can’t be super sure.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
People who trained one leg with a plan based on their own past workouts grew more muscle than when they used the same plan as everyone else.
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 560 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — 1.08 cm² is a measurable, meaningful difference in muscle size, and 50% more people benefited from personalized training.
- 2After 8 weeks, the leg trained with personalized volume grew 1.08 cm² more muscle than the leg with standard volume.
- 350% more people saw real muscle growth with personalized training.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Strength and Conditioning Research
Year
2020
Authors
Maíra C. Scarpelli, S. Nóbrega, Natália Santanielo, I. Alvarez, Gabriele B. Otoboni, C. Ugrinowitsch, C. Libardi
Related Content
Claims (6)
Everyone’s body responds differently to workouts—what works wonders for one person might be too much or too little for another, because of differences in genes, energy use, and how fast they recover.
Some people don't gain muscle with certain workout volumes, but they might grow a lot when switching to a different amount—meaning everyone might respond best to their own 'sweet spot' for lifting volume.
The total amount of effective resistance exercise performed for each muscle group in a week is the most important factor in determining how much muscle size increases.
If you adjust your weekly weightlifting routine based on your own workout history, you’ll likely build more muscle in your thigh compared to following a one-size-fits-all workout plan—after 8 weeks, the difference is about the size of a small coin.
People who already train regularly are more likely to see real muscle growth when their workout plan is customized for them, rather than using a one-size-fits-all routine — and the difference is about half as many more people seeing real gains.
If you're already experienced with weight training, doing the exact number of sets your past logs suggest (1.2 times your usual) builds more muscle than doing a fixed number of 22 sets every week — and this is shown by measuring your thigh muscle thickness with ultrasound.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.