Rate Coding

Jul 01, 2022

 Photo Credit: Pixabay

The rate of coding affects neuromuscular adaptations to resistance training in the following ways:

  • Motor unit recruitment
  • Nerve to-muscle conduction
  • Membrane potential and the electrophysiology involved

What is Rate Coding?

Rate coding: allows us to connect the brain to the muscle more efficiently

Through training, we can send action potentials more efficiently from the brain through the spinal cord, through a nerve to the muscle. As the brain is creating a signal, our body moves ions around through gradients (also known as the membrane potential), creating an action potential when the electrical signal crosses the membrane.

 
 
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When nerves are activated we are moving ions around to affect the nerve’s resting membrane potential.

A resting membrane potential is = ~ -70mv (millivots)

As this number increases (depolarizes), it reaches a threshold that signals the action potential to move down a nerve to a muscle. This process is a singular action potential, however we can look at multiple action potentials with rate coding. 

  • Single twitch muscles: Occurs from 1 action potential propagating (moving) down through a nerve.
  • Unfused tetanus: Occurs from 1 action potential and then another action potential propagating down through a nerve which allows for higher muscle recruitment.
  • Fused tetanus: Occurs from multiple action potentials continuously propagating quickly down through a nerve and not allowing the neuron to depolarize and repolarize fully. This accumulation produces the most force out of a muscle through higher motor recruitment.

Rate coding is one physiological mechanism that allows the recruitment of multiple muscle fibers to a higher extent because it increases intramuscular synchronization. Intramuscular synchronization allows the body to perform a movement pattern more efficiently.

Rate coding = the rate of action potential discharge to the muscle, which can accumulate to produce higher motor recruitment. 

Rate coding increases motor cortical activity in the brain:

The primary motor cortex is where the signal is generated, therefore higher recruitment here generates greater signals to the muscle.

  •  It improves the motor unit activity of higher threshold motor units:
  • If we train type II muscle fibers, we can recruit these fibers more efficiently to get the signal from the brain to the muscle more efficiently.

Rate coding promotes a higher rate of force development in the muscle:

This signal sending quicker will allow quicker ground contact time during depth jumps.

In summary, a higher rate of action potential discharge from improved rate coding is one of a number of variables that can improve muscle activation, jump height, vertical jump, cutting, running, and other athletic movements.


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