When measuring muscle activity with electrodes during bicep curls, the results can be affected by how the muscle stretches and where the electrode sits — so the numbers aren’t always a perfect measure of effort.

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Evidence from Studies

Supporting (1)

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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

When people did bicep curls with their arms in different positions, their muscle signals (EMG) got stronger—even though they lifted the same weight—showing that arm position affects the signal, not just how hard the muscle is working.

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No contradicting evidence found

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

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