Strength gains are determined mainly by the ability of the Central Nervous System (CNS) to generate force through the body and the structural integrity of the joints, tendons and muscles involved in the particular movement.
The way I see it, the CNS acts as headquarters of the body and controls the whole system by giving commands. The body is a slave to the mind. It cannot do anything without authorization. In this particular case, the body could be looked at as a bio-machine with the brain functioning as a central processing unit (CPU).
I understand that a CPU is not exactly a brain. While it does most of the calculations, the actual brain of a computer is the human using it. Machines don’t really have brains, but if they did, the CPU is the first candidate since it’s doing most of the thinking. In this article I will just use it as a synonym for machine brain, although I realize it is not entirely accurate.
Some people have amazing ability to generate enormous amount of force thanks to their powerful CNS. One could say that those individuals have really strong CPUs that work quite well during overclocking. However, even if you have a CPU that allows for insane overclocking (Black Edition or something), sooner or later the temperature will reach high levels, and the fun will end. When exposed to high enough temperatures even the most effecient CPU has no choice but to burn to death. This is when we experience CNS burnout.
So, what happens when we try to lift heavy weights?
In lifting CNS burnout happens quite often. When you are about to lift a heavy weight the CNS/CPU/brain needs to be cool/fresh in order to allow the muscles/software to run as smoothly as possible during a demanding task. You cannot expect from a computer with a CPU running at high temperatures to perform as good as a fresh one. There is a point where the heat needs to be reduced. Computers may have advanced air and water cooling systems but with humans it’s not that simple. We are not machines. Our cooling system is called time/rest.
They say that time heals everything, or at least most things. I am not entirely sure about that. Some things just get worse with time, but one thing is certain – what makes you sad in the evening can look possible to conquer in the morning, when your body and mind are fresher. That’s why people often sleep with an idea overnight before making a big decision. Very often your opinion changes afterwards. Employers interviewing future employees love the expression: “I have to sleep with the idea of you working here overnight.” It gives them an opportunity to cut you off politely, or at very least gains some time to think.
All of this shows the dual role of resting in lifting. The rest days are not just for the body. They are also for the mind/CPU. Even if all structural elements involved in a certain task are well rested, it does not matter when the brain is overloaded to the point where it cannot give efficient commands. You are distracted and weaker. Sometimes the CNS needs a lot more time to recover than the body.
A good example would be a heavy deadlift. It’s one of the exercises which require the CPU to be running at high speeds. The day after a heavy deadlift session you will often feel extremely tired. The CPU is still smoking and just thinking about exerting anywhere near the same amount of force will make you feel sick.
The CPU needs a lot of time to recover and get ready for it’s job as a chief commander. The body cannot do what the mind cannot conceive. Even if after 2-3 days your body feels rested, you may still feel unable to lift the same amount of weight because the CNS has not recovered yet.
This is also one of the reasons powerlifter take 5-10 days off before a competition. They want their CNS and body to be as fresh as possible for the challenge ahead. Time is needed to heal.
So, how do you know when your CNS needs to rest?
If before training, you are thinking: “Oh, no! I have to do this again!” you may be experiencing CNS burnout. However, there is difference between just being lazy and being mentally tired.
Sometimes the body is giving mixed symptoms, and when you lack basic lifting experience you may interpret them wrongfully. The truth is that just because you don’t feel like lifting, it does not mean that your CNS is in sleep mode. You can’t expect to feel like lifting every day.
One of the most certain signs that CNS burnout is taking place is being weaker during warm-ups and feeling unable to exert the same amount of force during your top set, despite knowing that you have the strength. Usually this type of fatigue is accompanied by lethargy and overtraining symptoms.
As expected, similar effect can be experienced even when it comes to sports that are not strength related. When I was in high school, I wanted to become a professional skateboarder. I was training almost every day. Consequently, I was also experiencing CNS burnout on frequent basis.
I remember one of the many times when I had a free day (no school). Free days for me meant all day training. That particular day I was feeling tired and did something very stupid. I didn’t know what to use to make coffee and just put a ton of it in a water bottle and shook it very hard. Stupid, right? I then drank most of it without vomiting and went to the park. Despite the coffee overload, I was feeling super tired from the accumulated fatigue over the previous weeks. I couldn’t do even some simple tricks. My mind was unable to concentrate and my legs were tired. I had no choice but to go home. I jumped straight into bed and couldn’t get out, although sleeping was not happening either. This is a perfect example of overtraining and CNS burnout. The same can happen with any kind of activity. Strength training, obviously, does not make an exception.
You can think of your rest days as sleeping. While some people may need less sleep than others, and the body can definitely adapt to mild sleep deprivation, you can’t possibly live without sleeping. That will kill you.
During extreme situations the CPU is immediately overclocked. By extreme I mean extreme. The highest level is obviously life threatening case or close to it.
Many years ago, me and a group of local boys decided to borrow/steal some fruits from a small semi-public garden. In the middle of our mission, out of nowhere, appeared a middle-aged man holding a heavy cudgel. Our reaction? Run and don’t look back.
Unfortunately, there was only one direction – straight forward. In order to reach the street, you had to jump off a 2 meter car garage. We all jumped right away without even thinking, except for one boy. I remember jumping without hesitation, landing like one of those parkour guys and then running downhill like a mad man. I didn’t even look for traffic. Since you are probably wondering, I will tell you. The boy we left behind got beaten by the guy. It was not that bad though. No serious injuries or anything like that too place, although for a long time the beaten boy attempted to play the role of a war victim.
This reminds me of another stupid story from my childhood. While we were looking for trouble on the roof of a relatively tall building, me and another guy decided to engage in a wonderful rebellious activity – throwing mud bombs. The target were cars parked in the area. It was nothing spectacular and we weren’t trying to damage anything.
At one point we decided to go down using the stairs when out of nowhere a middle-aged man appeared and started chasing us. He reminded me of the bad guy from the movie Heat. He had long hair, but the top of his head was reflecting the sunlight like a mirror.
We had no place to go but up. It was another time for a personal sprinting best. My CPU was overclocked right away.
As expected, we ended on the roof once again. The bad guy cornered us. I remember being very, very scared. I though I was going to die and almost pee myself. Fine. It was not almost.
Thankfully, we were very small and the multiple “please don’t, sir” had an effect on that guy. He let us go.
Some people are just better at overclocking.
Not everyone’s CPU can survive hard overclock. Some models are better than others. The same happens with lifting. There are people who are more efficient at generating force thanks to their CNS’s power.
Another important factor is definitely maturity. Many times I have seen teenagers who are bigger than me. That’s not very hard to achieve anyway. However, very often I can just feel that I can beat the hell out of them because of my age and CNS overclocking abilities. I am not planning on trying thought, at least without a very good reason.
Nevertheless, it is still good to know that my CNS is giving me permission to do so. This leads me to another topic – the permission to lift a heavy weight. Where do you think that comes from? King Head, of course.
To lift a heavy weight, you have to go all out. Obviously, that’s more pronounced when we are talking about 1 rep maxes. The truth is that the CNS will never allow you to gamble everything, unless you truly believe you have a decent chance to win. If the mind is not convinced that you can, you will never be able to exert your full physical force. You will always leave something in the tank and fail.
This is also what happens when you suffer an injury. For a long time the mind will not let you go all out, even if the injury has healed. It could even be an emotional thing like a break-up. There are people who just don’t want to deal with relationship related stuff after separation.
The CNS needs time to heal, cool off and get ready for the next challenge that’s about to come. We can’t just party all night forever. The king of this world is called time, and never misses an opportunity to remind us of its power.