The Study
Regional Hypertrophy: The Effect of Exercises at Long and Short Muscle Lengths in Recreationally Trained Women
This study watched two groups of women doing different bicep exercises and measured their arm muscles before and after. It found that one exercise seemed to make the lower part of the bicep thicker in that group, but we can't say for sure it was the exercise that caused it because other things might have played a role.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Women did one of two bicep curl exercises for 9 weeks. One curl stretches the muscle more at the start, the other at the end.
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 540 / 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.
- 1The growth from preacher curls is noticeable but not huge—useful if targeting specific arm areas.
- 2The 'preacher curl' made the lower part of the arm muscle grow by about 8.8%.
- 3The 'inclined curl' didn’t make any part grow much.
- 4Both curls gave similar overall results across arm regions.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Human Kinetics
Year
2023
Authors
Aitor Zabaleta-Korta, Eneko Fernández-Peña, J. Torres-Unda, Maider Francés, A. Zubillaga, J. Santos-Concejero
Related Content
Videos (2)
Claims (5)
Among women who train recreationally, preacher curls lead to more muscle growth in the elbow flexors than incline curls, especially toward the lower part of the muscle.
When performed by the same person, incline curls lead to more growth in the main bicep muscle, while preacher curls lead to more growth in the forearm muscles that help bend the elbow.
For women who work out regularly, doing preacher curls that stretch the biceps a lot might help build more muscle in the lower part of the upper arm—about an 8.8% increase—compared to other curl types.
Doing a specific type of bicep curl on an incline with changing resistance doesn't seem to make certain parts of the upper arm muscles grow more in women who work out regularly — even after doing it consistently for 9 weeks.
For women who work out regularly, both preacher curls and inclined curls build arm muscle just about the same way — no matter where you look along the upper arm.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.