When you go to exercise you are probably thinking about some of the ways you would like your body to adapt: lose fat, gain speed, gain strength, become more flexible…When you consider these things, have you ever stopped to think about how you adapt? If your thoughts immediately go to your muscles, then you are only halfway there. It is actually your brain and nervous system that adapt first. Let’s dive into this a little deeper.
All of our movement actions are linked to our nerves, specifically groups of them referred to as motor units. Motor units extend throughout our body and send the signal to move from our brains to our muscles. From a twitch in the eye to a long jump, movement is only achieved through motor unit action. It only makes sense that as we push ourselves to move in new and challenging ways, the nerves that enable us to move would adapt.
You may have noticed that when you first perform a new movement, such as a new type of lift, the movement may feel awkward and heavy, but over time it becomes more comfortable. This is due to adaptations in your nervous system. Your motor units begin to coordinate their actions better to allow for smoother movement, and your nervous system starts to recruit larger motor units at a faster pace in order to more readily handle heavier loads. This lets your muscles work together far more efficiently and enables you to work out harder. If these coordination adaptations never happened, then getting any kind of rigorous exercise would be very difficult, because your body would always be awkwardly navigating the movement pattern as if it were the first time.
The body helps in another way during exercise: it is constantly pumping the brakes in the nervous system to prevent us from going too fast or too hard, which serves to keep us from hurting ourselves when doing basic movements. Whenever you move a muscle, there is another muscle that acts to slow down your moving muscle. As we train, the opposing action of our muscles is reduced, and we are able to perform stronger actions. Similarly, the strength with which a motor unit activates also increases. This means we are capable of more because not only is the signal from our brain stronger, but our muscles oppose the movement action to a lesser degree.
You may think to yourself, “Why does this matter?” That is a fair question, so let’s dig into it. We need to understand how the body adapts so that we can have reasonable expectations of the changes we can expect from our exercise. Neural changes occur first, and we may not see any changes to muscle size until six weeks or so. In addition, we need to be aware that this element of neural adaptation is critical for us to learn how to smoothly perform new actions. If we only train the chest by doing the bench press, then we only have a movement pattern learned for the bench press. Instead, it is better for us to try many different kinds of exercises for the same muscle group, as this leads to increased variability in our movement patterns. Basically, this means that our brain learns many different ways to accomplish the same kind of training. This diversity in movement is extremely beneficial if for some reason we have to try a new movement for our exercises. This could happen because the bench press is full, the treadmill is out of order, or due to a knee injury you need to get your cardio training on the Upper Body Ergometer.
What does this mean for us when it comes to movement in our daily lives? Training the brain and central nervous system to accomplish new tasks is just as important as training our muscles. We need a nervous system that has been exposed to many different ways to move so that we can move more efficiently in many different scenarios outside of the gym. Lifting furniture, climbing a ladder, taking the stairs, getting a heavy dish out of the top cabinet – these are all activities that use muscular strength, and having worked those muscles in various ways helps you be ready for anything. I encourage you to change up your workout, try new machines, and try new kinds of movements that you have not before. Train your brain, and you have a lot to gain!
©Horton Doughton 2018
Needle, Alan. “Motor Units.” Appalachian State University, Feb. 2018, Boone, NC. Speech.
Needle, Alan. “Motor Variability.” Appalachian State University, Mar. 2018, Boone, NC. Lecture.
Baechle, Thomas R., and Roger W. Earle, editors. Essentials of Strength Training and Conditioning.
3rd ed., Human Kinetics, 2008.