The Claim

In untrained young men, cable biceps curl training performed with shoulder extension at approximately 50° does not result in greater biceps brachii hypertrophy compared to training with shoulder flexion at approximately 50°, despite theoretical muscle lengthening advantages, as both conditions produce similar relative growth (9% vs 6–7%) with no statistically significant difference (p > 0.05), indicating that moderate variations in shoulder angle during dynamic curls do not enhance hypertrophy when resistance is equated.

Source: Comparison Between Shoulder Flexed and Extended Positions in Elbow Flexion Resistance Training on Regional Hypertrophy and Maximum Strength: Preacher versus Bayesian Cable Curls

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
47score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Quantitative
1 study reviewed
In plain English

If you're a guy new to lifting, doing bicep curls with your arms in front of you or behind you doesn’t really make a difference in how much your biceps grow — both ways work about the same.

See the scientific wording

In untrained young men, cable biceps curl training with shoulder extension (~50°) does not produce greater biceps brachii hypertrophy than training with shoulder flexion (~50°), despite theoretically lengthening the muscle, with relative growth of 9% vs 6–7% and no statistically significant difference (p > 0.05), suggesting that moderate changes in shoulder angle within dynamic curls do not confer a hypertrophic advantage when resistance is equated.

What the research says

1 study
  1. Study: Comparison Between Shoulder Flexed and Extended Positions in Elbow Flexion Resistance Training on Regional Hypertrophy and Maximum Strength: Preacher versus Bayesian Cable Curls

    The study found that changing arm position during cable curls didn’t lead to noticeably more muscle growth, which matches what the claim says.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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