Today I was talking to a friend about hypertrophy and it reminded me how much I enjoyed learning about body adaptations to exercise! There's a lot of misconceptions and curiosity when it comes to what actually happens to your skeletal muscles and your body when you workout. In light of that, we’re introducing a new series: Adapting to Exercise. This week we'll be looking into the basic neurological adaptations your body makes to strength training! Stay tuned for the next post in this multi-part series!
Neurological Adaptations
These are criminally underrated adaptations as they are critical to increasing your strength. To understand the adaptations, here’s a quick summary of how nerves impact our muscles:
The nervous system can be divided into the central (CNS) and peripheral (PNS) nervous system. The PNS is everything minus the brain and spinal cord and can be further divided into the autonomic (ANS) and somatic (SNS) nervous system. We’ll be focusing on the somatic nervous system here as that is the system associated with voluntary control of skeletal muscles.
A simplified version of getting a skeletal muscle (ex. your bicep) to contract starts with a motor unit. This is a "package deal" which involves a motor neuron and all the muscle cells it innervates (supplies). If you want to contract your bicep to lift a small 1 lbs weight, a few motor units are recruited. This causes the associated motor neurons to fire which sends a signal to each of the muscle cells it supplies, telling them to contract. Motor unit recruitment depends on how much your muscle needs to contract. As the weight demand increases, more motor units are recruited to respond to the increased weight!
In addition to having large and small motor units, motor units are also “all or nothing” which means once the associated motor neuron is fired, EVERY muscle cell supplied by that motor neuron will contract. So smaller motor units are recruited first to allow for small movements to occur. If that wasn't the case, and large motor units were recruited first, your muscles would contract too hard and you would have a hard time handling anything that is easily breakable.
Now, back to the adaptations:
3 Neurological Adaptations
1) Increased Muscle Activation
High threshold motor units, aka large motor units, can only be recruited during a maximal contraction and untrained individuals may not be able to recruit them. Through training, your body will be able to utilize them.
2) Decreased Antagonist Contraction
The antagonist is the muscle group opposing the agonist - the muscle you are trying to activate (the triceps is the antagonist to biceps in a biceps curl). Co-contraction (both agonist and antagonist active) during a movement is common for stability. However, reducing antagonist contraction will maximize agonist contraction as it won’t have as much resistance.
3) Increased Rate of Force Production
Maximal force can be achieved quicker, for example, in ballistic movements such as jumping.
As you can see, the neurological system is complex but I hope we made it simplified enough to understand the basics! We'll continue to go into more depth regarding neurological adaptations and also branch into the science of hypertrophy in future parts.
Stay tuned!
Comentários