The Claim

Eight weeks of resistance training focusing on the final range of motion (68°–135°) of the elbow flexors does not result in significantly greater biceps hypertrophy, as measured by summed cross-sectional area at 50% and 70% humerus length, compared to training through the initial range of motion (0°–68°) in untrained young women.

Source: Training in the Initial Range of Motion Promotes Greater Muscle Adaptations Than at Final in the Arm Curl

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
46score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Description
1 study reviewed
In plain English

In untrained young women, training the biceps through the fully bent position of the elbow for eight weeks does not lead to more muscle growth than training through the partially bent position, when measured by muscle size at specific points along the upper arm.

See the scientific wording

Training the elbow flexors through the final range of motion (68°–135°) for eight weeks does not produce significantly greater overall biceps hypertrophy than training through the initial range (0°–68°), as measured by summed cross-sectional area at 50% and 70% humerus length in untrained young women.

Why this might work

When you lift with your arm mostly straight, your biceps muscle is stretched more at the start of the movement. This stretch creates more pull on the part of the muscle closer to the elbow, which triggers chemical signals that tell the muscle to grow more in that area. When you lift with your arm mostly bent, the stretch is less, so the muscle doesn't grow as much in that same spot. Both ways make your whole biceps bigger overall, but the stretched position just makes one part grow more.

Supported mechanismbased on 1 study

What the research says

1 study

  1. Study: Training in the Initial Range of Motion Promotes Greater Muscle Adaptations Than at Final in the Arm Curl

    This study found that training your biceps with your elbow mostly bent (final range) doesn't make your biceps grow bigger overall than training with your elbow mostly straight (initial range). Both ways worked about the same for total muscle growth.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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