The Claim
In untrained men, performing cable curls to momentary failure over a 10-week period results in similar elbow flexor hypertrophy (7–9% increase) regardless of whether the shoulder is held in neutral or maximally extended position, when resistance profiles and effort are matched.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
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.
See the scientific wording
Untrained men achieve similar elbow flexor hypertrophy (7–9% increase) from cable curls performed to momentary failure over 10 weeks, regardless of whether shoulder extension is neutral or maximally extended, provided resistance profiles and effort are matched.
When someone lifts a weight until they can't do another rep, the muscles are stretched and pulled with enough force to activate signals that tell the body to build more muscle tissue. It doesn't matter if the arm is held straight back or relaxed at the side — as long as the weight feels just as hard to lift and the person pushes until they truly can't move it anymore, the muscle gets the same strong signal to grow.
What the research says
1 studyStudy: The effects of shoulder extension angle on elbow flexor hypertrophy in the cable curl exercise
When untrained men did cable curls with their shoulder either relaxed or pulled back — as long as they pushed until they couldn’t do another rep and the weight felt the same — their biceps grew just as much either way.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.