When the resistance is set to be equal at the beginning of the movement, both shoulder-extended cable curls and neutral-position barbell curls produce similar levels of muscle growth in the biceps.

We analyzed the available evidence on whether shoulder-extended cable curls and neutral-position barbell curls build similar amounts of biceps muscle when resistance is matched at the start. What we’ve found so far is that 60.0 assertions support the idea that both exercises lead to similar levels of muscle growth under those conditions, and none refute it [1]. This means that when the weight feels the same at the beginning of each movement — regardless of how the arm is positioned or the type of equipment used — the biceps appear to be challenged in a comparable way. The shoulder-extended cable curl involves holding the cable with the arm stretched out in front, while the neutral-position barbell curl uses a straight bar with palms facing up and arms at the sides. Even though the mechanics differ, the evidence suggests that when resistance is equalized at the start, the biceps respond similarly over time. We don’t know why this might be the case, or whether differences in tension throughout the range of motion affect long-term results. The evidence we’ve reviewed doesn’t address factors like time under tension, muscle activation patterns beyond the start point, or individual variation in response. For someone choosing between these two exercises, the takeaway is simple: if you set the same starting resistance, either one can be used to target the biceps without assuming one is clearly better than the other. The choice may come down to comfort, equipment access, or personal preference rather than muscle-building advantage.