The Claim

Eight weeks of resistance training targeting the elbow flexors through an initial range of motion (0°–68°) produces greater hypertrophy at the distal region of the biceps brachii (at 70% humerus length) compared to training through the final range of motion (68°–135°), with no significant difference in hypertrophy observed at the mid-region (50% humerus length) 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.

Cause and effect
1 study reviewed
In plain English

In untrained young women, performing bicep exercises through a shorter range of motion (from fully extended to halfway bent) leads to more muscle growth near the elbow than using a longer range (from halfway bent to fully bent), but both approaches result in similar muscle growth in the middle of the bicep.

See the scientific wording

Training the elbow flexors through the initial range of motion (0°–68°) for eight weeks results in greater hypertrophy at the distal region of the biceps brachii (70% humerus length) than training through the final range (68°–135°), but no significant difference is observed at the mid-region (50% humerus length) in untrained young women.

Why this might work

When you lift weights starting with your arm straight, your biceps muscle is stretched more at the start, which puts more pull on the lower part of the muscle. This extra pull triggers chemical signals that tell the muscle to build more protein and grow bigger in that specific area, while the middle part doesn't get the same extra stimulus.

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 doing arm curls starting from a straight elbow (partial range) made the lower part of the biceps muscle grow more than doing curls from a bent elbow, but both ways made the middle part grow the same. So, if you want bigger lower biceps, start your curls from the bottom.

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

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.