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.

Scientific Claim

The acute muscle strain response (measured by echo-intensity) in the distal biceps brachii is greater after resistance training involving shoulder extension (-30°) compared to a neutral shoulder position, indicating that lengthened-position training induces localized strain.

Original Statement

“ES analysis suggests that magnitude of effect was larger in the VAR when compared to CON condition (ES; 1.04 vs. 0.60), respectively... VAR condition performed three working sets in a lengthened position for the long head of the biceps (−30 degrees glenohumeral extension).”

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 controlled inclusion of lengthened-position sets in VAR and the quantified effect size difference support a definitive causal claim for localized strain.

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 whether doing bicep curls with your arm stretched back (shoulder extension) causes more muscle strain than doing them with your arm at your side, but it found no difference in muscle strain between the two — so the claim isn’t backed up.

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.

89%

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.

82%

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.

79%

After a tough bicep workout, your muscles swell and show stress signs, but they bounce back fully by the next day — so these signs don’t tell you much about long-term growth.

75%

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

74%