Analysis Version
v1
History
Back
causal
Analysis v1
Contested

Working your biceps with your arms stretched back might grow the upper part of the muscle a bit more than doing curls with your arms already in front of you.

49
Pro
60
Against

Evidence from Studies

Supporting (1)

49

Community contributions welcome

49

Distinct muscle growth and strength adaptations after preacher and incline biceps curls

Randomized Controlled Trial
Human
2025 May

The study found that doing bicep curls with arms stretched back (incline curl) built more muscle near the top of the biceps compared to curls with arms stretched forward (preacher curl), which matches the claim.

Contradicting (3)

60

Community contributions welcome

60

The effects of shoulder extension angle on elbow flexor hypertrophy in the cable curl exercise

Randomized Controlled Trial
Human
2026

The study tested whether curling weights with arms behind the body builds bigger biceps than curling with arms at the sides. It found no meaningful difference in muscle growth between the two positions.

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 compared bicep curls done with the arm in front versus behind the body to see which builds more muscle. Even though the 'arm behind' version had slightly higher numbers, the difference wasn’t big enough to say one is better than the other.

47

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 compared biceps workouts with the arm in front versus behind the body and found both increased muscle size equally—there was no real difference.

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.

Similar Assertions

Whether you're working your quads, calves, or biceps, stretching them fully during exercises helps them grow bigger — this works for many different muscles, not just one.

45
0
83%

If you're a guy new to lifting, doing bicep curls with your arms in front of you or behind you doesn’t really make a difference in how much your biceps grow — both ways work about the same.

47
0
82%

If you're already strong and you train your arms using only the part of the movement where your muscles are stretched (like holding the bottom of a bicep curl), you'll build just as much arm muscle as if you did the full movement — the stretch alone seems to be all you need.

67
0
79%

When you stretch your muscles fully during workouts, the ends of the muscles grow more than the middle parts — the stretch makes the muscle ends bulk up more than the center.

0
0
78%

For guys new to lifting, doing bicep curls with your arms in front of your body works just as well for building arm muscle as doing them with your arms behind you — both give about the same 6% to 9% growth in 10 weeks.

47
0
77%

Related Content