The Study
The Effects of Varying Glenohumeral Joint Angle on Acute Volume Load, Muscle Activation, Swelling, and Echo-Intensity on the Biceps Brachii in Resistance-Trained Individuals
This study shows that changing shoulder angles during bicep curls might make the muscle work a bit harder during the workout, based on electrical activity. But it only looked at what happened right after the workout in a small group of trained people, so we can’t say for sure if it leads to bigger muscles over time.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study checks if doing bicep curls with different arm positions makes your muscles work harder.
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 559 / 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 increase in muscle activity and strain suggests slightly more growth stimulus without extra weight or reps, which could help muscle building over time.
- 2Changing arm positions increased muscle activity by 8.4–23.3%, caused more muscle swelling right after exercise, and led to higher strain in the lower biceps.
- 3Total work was the same in both routines.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Sports
Year
2019
Authors
Christopher Barakat, R. Barroso, Michael R Alvarez, Jacob T. Rauch, Nicholas Miller, Anton Bou-Sliman, E. D. De Souza
Related Content
Claims (6)
If you're used to lifting weights, changing the angle of your arm during bicep curls in one workout can make your muscles work harder—even though you're doing the same amount of lifting.
After a bicep workout, your muscle swells up right away — by about 12% — but that puffiness goes away within a day, even if you changed up your arm angles during the workout.
Changing the shoulder angle during bicep curls makes your biceps work harder, even if you're lifting the same total weight — your muscles fire more, according to electrical activity measurements.
When you move your arm backward, it stretches your biceps because the muscle runs over your shoulder joint — and when you move your arm forward, the biceps gets shorter.
If you're used to lifting weights, changing the angle of your shoulder during bicep curls doesn't make your workout easier or harder — you still do about the same amount of work as with a fixed angle.
Changing your shoulder angle while doing bicep exercises seems to cause more muscle swelling and strain in the lower part of your bicep right after the workout, especially if you do moves that stretch the muscle.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.