The middle part of your bicep gets a little more 'hazy' on ultrasound after a workout, but it clears up by the next day — and it doesn’t matter if you changed your shoulder angle.

Scientific Claim

Echo-intensity in the mid-belly of the biceps brachii increases acutely after resistance training but returns to baseline within 24 hours in resistance-trained individuals, with no significant difference between constant and varied glenohumeral joint angle conditions.

Original Statement

“For mid-belly echo intensity (MBEI), there was a significant main time effect (p = 0.0001)... The MBEI returned to baseline 24 h post similarly across conditions.”

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

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

definitive

Can make definitive causal claims

Assessment Explanation

The repeated-measures design and statistical analysis support a definitive conclusion of acute, transient strain without condition-specific modulation.

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 looked at how different arm positions affect muscle activation during bicep curls, but it never measured or reported the echo-intensity changes that the claim is about, so we can't say if the claim is true or false based on this study.

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

When you do bicep curls with your shoulder stretched back, the lower part of your bicep shows more signs of stress on ultrasound right after the workout than when you keep your shoulder neutral.

92%

Doing bicep curls with your arm stretched behind you makes the lower part of your bicep feel more strained right after the workout than doing them with your arm at your side.

82%

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

80%

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.

80%

The second time people do a tough arm workout, their muscles show less 'swelling' on ultrasound scans, meaning there's probably less damage or inflammation.

76%