In young women who haven't trained before, doing bicep curls with one arm at a time may lead to a small increase in strength in that arm compared to using both arms together, but both methods produce...
Mechanism
Synthesis from 1 study
Lifting one arm at a time makes your brain send stronger signals to that arm’s muscles, helping you lift heavier without making the muscle bigger. Lifting both arms together doesn’t boost the brain’s signal as much, so you don’t get as strong — but your muscles grow just as much either way.
Most probable mechanism
When you lift one arm at a time, your brain sends stronger signals to the muscles in that arm, making them contract more forcefully. This helps you get stronger without making the muscle bigger. Training both arms at once doesn’t trigger the same level of brain signal boost, so strength gains are smaller, but muscle growth stays the same either way.
Unilateral training increases corticospinal drive to the active motor units in the trained limb
Increased neural drive enhances motor unit recruitment and firing rate during maximal voluntary contractions
No significant difference in muscle fiber cross-sectional area or total muscle volume occurs between unilateral and bilateral training conditions
Evidence from Studies
Supporting (1)
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Small muscle mass exercise enhances muscular adaptations? Effects of unilateral and bilateral biceps curl on maximum strength and muscle size changes.
Contradicting (0)
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