There is a simple truth that any one that does crossfit, powerlifting, bodybuilding, endurance training, or any other type of physical fitness training will understand. “We are what we repeatedly do: Our body has learned to adapt and will adapt as long as it feels the need. So in order to get better, stronger or faster, we must first understand the mechanisms that cause it to happen.
But HOW do we get better? There are three different areas that we improve in; Central Nervous System, Hypertrophy, and Energy Systems.
Central Nervous System
Our Central Nervous System, or CNS, is comprised of our brain, spinal cord and nerves. This system of neurotransmitters created our ability to communicate and contraol out body. If our body was our car, it would be the wires, controls, sensors, computer and spark plugs. We are training our CNS every time we move, experience, feel. From a training stand point we think of this as practice, and it results in better balance, coordination, accuracy and agility.
When we Practice, we are giving our body a stimulus. Taking for example: Learning how
to do double-unders. When we practice, our brain is sending signals to our body to coordinate how we move, in return it also receives input about how that movement was performed. Our CNS starts to determine what signals to send to what muscle groups and when. The more that we practice, the more these nerve endings get activated. Our body in an attempt to make this mind, nerve, muscle connection stronger, begins to cover these nerve cells with a substance known as myelin. This added coating of myelin increases the speed that the information can travel along this nerve, and makes the signal more efficient.
Imagine driving down a dirt road where the speed limit is 45. As you get up to speed, there is more dust getting kicked up and the tires will start to slide a little. Take that same dirt road and pave it, making the road smoother and less bumpy. Instead of the speed limit being 45, you can now travel at 65. As more and more cars start traveling along that road, it will eventually turned into a highway.
Every time we practice, we are really building a road out of our nerve cells. More practice equals more myelin. This also speaks to the quality of our practice. Better signals contribute to better control of our muscle groups. This is the importance of perfect practice. Sloppy practice results in highways to places your body doesn’t need or want to go. It is much easier to build the right road than it is to build the wrong road and have to rebuild it later. Early in someone’s training life, we want to spend the time to make sure that people are doing the movements correctly. They are safer and end up getting better because of it.
So now that we understand a little about our Central Nervous System, what is Hypertrophy?
If the central nervous system is the wires and controls of our car, then our muscles are our drive train. Our muscles generate force, and apply it to the road. Hypertrophy is the science of the growth of our muscles. First we rely on our CNS to fire the right muscles. Once that is the case, we start by producing a stressor to stimulate our muscles, usually in the form of resistance. We add resistance and ask our muscles to perform contrary to this resistance. This resistance is usually external to us and in the form of everything from barbells, medicine balls, kettle bells, or utilizing gravity as our resistance. Our body will adapt in an attempt to be prepared to over come this resistance when encountered again.
Our muscles are made of muscle fibers. These muscle fibers are either on or off. This means they are either contracting as hard as they can or they are relaxed. When we train our CNS we are teaching our body to control when and how many muscle fibers are being used. “Getting stronger” is the result of our body firing more muscle fibers or from hypertrophy. Hypertrophy is the increase in volume or density of the muscle fibers. This results in greater contractile force.
When someone does a bicep curl of 25lbs, the CNS will activate and fire the muscle fibers needed to over come this weight. In this case it might only be 50% of the muscle fibers of the bicep. When 10lbs is added, the amount of muscle fibers needed may increase to 60%. Through training you may come to the point where the increased volume and density of these fibers allows you to only need 35% of your muscle fibers to lift the 25lbs.
Now that we have our CNS and our Muscles on board, the last thing that we need to adapt is our energy systems.
The Energy Systems: Aerobic vs Anaerobic
Our energy systems can be compared to the fuel and engine of our car. There are two basic ways that we fuel the different needs of our body. These two styles are aerobic and anaerobic.
Aerobic means that our movement and activity is being powered by our ability to inhale and utilize oxygen as an energy source. Aerobic activities generally include light to moderate exercise. When we breathe we absorb oxygen in our lungs, it gets transported to our various cells, and we expel carbon dioxide as waste. The interesting part is that in the process of breathing in and out, we are not able to absorb all of the oxygen and as a result end of breathing out some of that oxygen. One way that we measure our aerobic ability is by measuring the amount of oxygen that we can absorb within each breathe, known as VO2 Max. Training allows us to use more of the oxygen that we do breathe in. It also allows us to expel the exhaust that we create in the form of carbon dioxide.
Our intensity dictates what system we are using. If we are doing sprints or other short duration high intensity activities, then we are most likely using out anaerobic system. One way to understand that is to sprint as fast as you can or as long as you can before you have to slow down. Your body first starts to use the anaerobic system, but upon realizing that you are asking for more energy than oxygen can provide you body switches to burning glucose as fuel. This is a more powerful fuel source but it creates lactic acid as a by product. Our ability to utilize glucose and remove lactic acid from our muscles and blood stream is characterized as our Lactate Threshold.
In both aerobic and anaerobic our ability to perform greatly relies on our ability to purge our system of waste, in the forms of carbon dioxide and lactic acid. This build up of waste is what causes our performance to decrease and potentially fail.
Take for example holding your breath. The longer you hold your breath, the harder it is to hold. Your desire to breathe is not as much of a need to take in more oxygen, but more so a need to get rid of carbon dioxide. Your body’s cue that it needs to breathe is from that build up of carbon dioxide, without it you would just pass out from lack of oxygen. Similarly the build up of lactic acid, is the cause for muscle fatigue. Our training improves the efficiency with which we use our fuel and our ability to process its waste counterparts.
In the end, we all want to get better. If we take a moment to understand the process that occurs every time we run a lap or pick up a weight, we then begin to understand the value of our efforts. The details go much further than what is included here, but it gives us a clue into the greater systems at work. We work hard, but we can also work smarter.