The Study
Muscle Hypertrophy and Strength Adaptations to Systematically Varying Resistance Exercises
This study gave two groups of young women different workout plans and found they both got just as strong and muscular. Because they were randomly assigned, we can guess that the workout plan caused the results—not something else. But we can't say it works the same for everyone.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Two groups of young women lifted weights three times a week for 10 weeks—one group did the same exercises every time, the other switched exercises 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 548 / 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.
- 1Switching exercises didn’t help more than sticking to the same ones—so if you’re training hard and doing enough volume, variety isn’t needed for gains.
- 2Both groups got about the same stronger and muscles grew about the same amount: 7.5–19.3% vs.
- 37.8–17.7% muscle growth, and 24–32% vs.
- 429–30% strength gain.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Research Quarterly for Exercise and Sport
Year
2024
Authors
Witalo Kassiano, Bruna Costa, Gabriel Kunevaliki, J. Nunes, Pâmela Castro-e-Souza, Jainara de Paula Felipe, Ian Tricoli, A. Luiz, V. Tricoli, Edilson S. Cyrino
Related Content
Claims (3)
When the total amount and intensity of workout effort are kept the same, performing more than one type of isolation exercise for each muscle group does not lead to greater muscle growth.
If you mix up your workout reps—sometimes doing just a few, sometimes a bunch—your muscles grow about as much as if you always stuck to the usual 8 to 12 reps per set.
In young women, doing resistance training three times a week for 10 weeks with either the same exercises or varied exercises leads to similar improvements in leg muscle thickness and strength, meaning changing exercises does not produce better results.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.