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Claim
Strong Support
causal
Analysis v3

If you're new to lifting and do cable curls the same way each time, it doesn't really matter whether your arms are stretched far back or in a neutral position — your biceps will grow about the same...

60
Pro
0
Against

Mechanism

Synthesis from 1 study

How it works

When you curl a cable with the same weight, same number of reps, and same effort, your biceps get the same workout whether your arm is pulled back or relaxed. That means the muscle fibers are stretched and squeezed the same way, so they grow the same amount either way.

Most probable mechanism

In Simple Terms

When the biceps are worked with the same amount of resistance, same range of motion, and same level of effort, the muscle fibers experience similar levels of stretch and force regardless of whether the shoulder is pulled back or kept relaxed. This similar force and stretch triggers the same cellular signals that tell the muscle to grow, so the muscle gets about the same bigger either way.

Causal chain
1

Elbow flexor muscles are subjected to identical external resistance and joint kinematics during concentric and eccentric phases of the curl, resulting in comparable levels of muscle fiber strain and tension.

Verified by multiple studies
which leads to
2

Mechanical tension on muscle fibers activates intracellular signaling pathways, including mTORC1 and MAPK, which initiate protein synthesis and suppress protein breakdown.

Supported by evidence
which leads to
3

Metabolic stress and muscle damage are held constant across conditions due to matched effort, repetition volume, and range of motion, leading to equivalent anabolic signaling and satellite cell activation.

Supported by evidence
which leads to
4

Net protein balance remains positive and similar over the 10-week training period, resulting in consistent increases in muscle fiber cross-sectional area and overall muscle thickness.

Verified by multiple studies

Evidence from Studies

Supporting (1)

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

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.

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Source Study

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

Score: 60
DOI: 10.3389/fphys.2026.1750722

Similar Assertions

In untrained men performing cable curls with the same resistance, movement range, and effort, changing the shoulder angle between neutral and fully extended positions leads to similar increases in elbow muscle thickness after 10 weeks of training.

60
0
95%

If you do cable curls the same way every time except for where your shoulders are, it doesn’t really matter for building arm muscle—even if you can lift heavier when your arms are stretched out.

60
0
91%

In men who are new to strength training, doing cable curls until muscle fatigue for 10 weeks leads to about the same increase in bicep muscle size whether the shoulder is kept straight back or pulled slightly backward, as long as the resistance and effort level are kept the same.

60
0
89%

If you're new to lifting, changing your arm position during cable curls doesn't make one part of your biceps grow more than another — both positions give you the same kind of muscle growth over 10 weeks if everything else is kept equal.

60
0
88%

Doing bicep curls with your arm in front of your body or behind your body gives you the same muscle growth and strength gains if you're using the same amount of weight and doing the same number of reps.

54
0
87%