Your bicep doesn't grow more at the top, middle, or bottom no matter how you do the curl — it grows evenly all along its length.

54

Pro

0

Against

Evidence from Studies

Supporting (1)

54

Community contributions welcome

54

Comparison Between Shoulder Flexed and Extended Positions in Elbow Flexion Resistance Training on Regional Hypertrophy and Maximum Strength: Preacher versus Bayesian Cable Curls

Randomized Controlled Trial

Human

2025 Apr

The study found that doing bicep curls with your arm up or down made no difference — your bicep grew evenly along its whole length either way, meaning it doesn’t grow more at the top or bottom.

Contradicting (0)

0

Community contributions welcome

No contradicting evidence found

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

Source Study

Comparison Between Shoulder Flexed and Extended Positions in Elbow Flexion Resistance Training on Regional Hypertrophy and Maximum Strength: Preacher versus Bayesian Cable Curls

Score: 54

DOI: 10.1002/ejsc.12279

Similar Assertions

Your bicep doesn’t work harder or softer when you turn your hand palm-up, palm-down, or straight ahead — it just keeps doing the same amount of work.

26

0

84%

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.

0

51

80%

When you bend your elbow and twist your forearm at the same time, your biceps work harder, but the muscles on the side of your arm work less — your body doesn’t just turn muscles on or off the same way every time.

21

0

80%

When your palm is up or straight, your bicep gets stiffest when your elbow is bent at 60 degrees — but if your palm is down, it gets less stiff the more you bend your elbow.

34

0

79%

When you bend your elbow with a light weight, your bicep works hardest when your palm is facing up and your elbow is halfway bent — and it works least when your palm is facing down.

34

0

79%