After four weeks of one-sided leg training with restricted blood flow, the opposite leg does not become stronger or develop larger muscles, even if the trained leg does.
Mechanism
Synthesis from 1 study
Training one leg makes the brain send stronger signals to the other leg, helping it contract faster at the start of a movement. But that stronger signal doesn't make the muscle in the other leg grow bigger or stronger over time — it only helps it turn on quicker.
Most probable mechanism
When one leg is trained hard or with a tight band around it, the brain sends stronger signals to the opposite leg, making it contract faster. But this stronger signal doesn't make the muscle in the opposite leg grow bigger or stronger in the long term — it just helps it turn on more quickly at the start of a movement.
Unilateral resistance training induces neuroplastic changes in the motor cortex, increasing descending neural drive to the contralateral spinal motor neurons.
Enhanced descending drive increases synchronous recruitment of motor units in the contralateral muscle during the initial phase of contraction, improving rate of force development.
The increased neural activation does not trigger signaling pathways that stimulate muscle protein synthesis or satellite cell activity, resulting in no measurable change in muscle cross-sectional area.
Evidence from Studies
Supporting (1)
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Contralateral training effects of low-intensity blood-flow restricted and high-intensity unilateral resistance training
Contradicting (0)
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