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.

Scientific Claim

Varying glenohumeral joint angles during biceps curls increases total biceps brachii muscle activation by 8.4% to 23.3% in resistance-trained individuals, without altering total volume load, indicating that internal neuromuscular demand can be elevated independently of external work output.

Original Statement

“However, the overall session EMG amplitude was significantly higher (p = 0.0001) in VAR compared to CON condition (95%-CI: 8.4% to 23.3%).”

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 study is a Level 1b RCT with randomization and crossover design, allowing causal inference for acute outcomes. The verb 'increases' is appropriate given the controlled conditions and significant p-value.

Evidence from Studies

Supporting (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

Changing the angle of your shoulder while doing bicep curls made your biceps work harder—without lifting more weight or doing more reps—so your muscles get a bigger challenge just by moving differently.

Contradicting (0)

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

Similar Assertions

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

86%

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.

85%

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.

83%

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

78%

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.

77%