Your muscles are controlled by the nerves in your brain. Each nerve is connected to several individual muscle fibers, so just one neuron is needed to get several muscle fibers contract at once. However not all of the motor units contract at once. So you could flex your bicep, but maybe only half of the muscle fibers would be activated. The stronger the contraction, the more motor units that are recruited to produce a stronger force. This is called motor recruitment.

Your muscles are controlled by the nerves in your brain. Each nerve is connected to several individual muscle fibers, so just one neuron is needed to get several muscle fibers contract at once. However not all of the motor units contract at once. So you could flex your bicep, but maybe only half of the muscle fibers would be activated. The stronger the contraction, the more motor units that are recruited to produce a stronger force. This is called motor recruitment.

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