Just because changing your shoulder angle makes your biceps work harder during one workout doesn’t mean it will make your muscles bigger over time — this study didn’t test that.

Scientific Claim

Varying glenohumeral joint angles during biceps curls does not produce differential long-term muscle growth or adaptation outcomes in resistance-trained individuals, as the study measured only acute physiological responses.

Original Statement

“However, we cannot draw conclusions on how this may influence chronic adaptations, as this was an acute study.”

From 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

Evidence Quality Assessment

Claim Status

overstated

Study Design Support

Design supports claim

Appropriate Language Strength

association

Can only show association/correlation

Assessment Explanation

The authors overstate implications for chronic adaptation, but the study design (acute only) cannot support such claims. The corrected version must reflect absence of evidence.

Evidence from Studies

Supporting (0)

No supporting evidence found

Contradicting (1)

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

Randomized Controlled Trial

Human

2019 Sep 4

The study found that changing arm angles during bicep curls made the biceps work harder during the workout, even though it didn’t track long-term muscle growth. This suggests that varying angles might help muscles grow more over time, so saying it doesn’t matter is not supported.

Source 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

Score: 51

DOI: 10.3390/sports7090204

Similar Assertions

Whether you change your shoulder angle or not during bicep curls, your muscles recover at the same speed over the next three days.

87%

Even when you change your shoulder position during bicep curls, you still lift the same total amount of weight — your total workout effort doesn’t go up or down.

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Changing the angle of your shoulder while doing bicep curls makes your biceps work harder during the workout, even if you're lifting the same total weight.

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Switching up your shoulder position during bicep curls makes your muscles fire more, even if you're lifting the same total weight.

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After a tough bicep workout, your arm gets a little swollen, but it goes back to normal by the next day — and it doesn’t matter if you changed your shoulder angle during the workout.

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