The Study
Neuromuscular Adaptations to Unilateral vs. Bilateral Strength Training in Women
This study is like a fair race between two groups of girls who trained their legs differently — one used one leg at a time, the other used both legs together. It shows that using one leg at a time made each leg stronger on its own, but both ways made their legs just as big and strong together. So we know which way helped each leg get stronger by itself — but not that one way is better overall.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Training one leg at a time makes that leg stronger and more active, but both ways make your legs equally strong overall.
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 547 / 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 — if you want one leg to be much stronger (e.g., for sports), train it alone; if you want both legs to work together better, train them together.
- 2One-leg training: +21.4% strength, +39.9% muscle activity.
- 3Two-leg training: +10.3% strength, +12.0% activity.
- 4Both: same muscle growth and total strength gain.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Strength and Conditioning Research
Year
2016
Authors
C. Botton, R. Radaelli, E. Wilhelm, Anderson Rech, L. Brown, R. Pinto
Related Content
Claims (7)
For small muscle groups, unilateral and bilateral resistance training produce equivalent hypertrophic adaptations when volume and effort are matched.
Performing resistance exercises with one limb at a time may lead to greater activation of nerves and muscle fibers than using both limbs together, due to lower suppression of nerve signals during single-limb movements.
Whether you train one leg or both legs at once for 12 weeks, your legs get just as big and strong overall — the way you do the exercise doesn’t change how much muscle you build or how strong you become in general.
Training one leg at a time makes it harder for both legs to work together at full power, while training both legs together makes them work better together — the way you train changes how your legs coordinate.
Doing leg extensions one leg at a time for 12 weeks makes each leg stronger and more active when tested alone, better than doing both legs together — even though both methods improve overall leg strength similarly.
If you train one leg at a time, that leg gets much stronger than the other when tested alone — but if you train both legs together, both legs get stronger at the same rate, with no one leg getting ahead.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.