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Posted on 01-23-2013
By: Dr. Sten Ekberg
I had a patient come in after having hurt her back training with kettlebells. She is usually very active and takes good care of herself so she was wondering why she had hurt herself after a less than exhausting workout with the kettlebell.
As a functional neurologist, it is with great interest that I see the recent trend in gyms and training facilities towards core strength, free weights and unstable platforms, because they all serve to challenge the brain to greater levels. I’m also writing this article with a word of caution to help people better understand what’s involved. I am very much in favor of all these newer types of training because they are a form of exercise that is geared towards the type of function based health that we talk about in the office, but we need to know a little bit more before diving in head first.
For chiropractors trained in functional neurology it is very obvious why these new trends are so popular and why they are getting such great results. It is simply because complexity challenges the brain and nervous system more. The whole point of exercise is to maintain and challenge the body, but since the brain regulates every aspect of the body, all exercise is really primarily brain exercise. Just like a muscle will respond and grow with a challenge, the brain is not stagnant, but rather very flexible. This relatively new discovery is what is referred to as neuroplasticity. We often don’t think of the brain as performing physical work, because we have very limited awareness of the brain itself. The brain “feels” for the rest of the body, but we cannot feel the brain itself.
In terms of physical labor, and consequently production of heat, the brain is very hard working. Even though it only makes up 2% of our body mass it consumes 20% of the energy. The work that it does though is unique in the body; its primary job is to process electrical signals. The brain cannot see, hear, touch, taste or smell anything, but it interprets these signals from the body’s receptors and puts them together into a complete picture of our environment.
When it comes to exercise the simplest and therefore least challenging for the brain is single plane movement without having to balance. A little more complex is an exercise with alternating planes of motion, and still more complex is multiple planes of motion without any repeating pattern. Then as we add the challenge of having to stand up and balance against gravity or even add an unstable platform it becomes even more complex and challenging.
The core is the foundation of all movement because it provides a stable platform for all other movements of the arms and legs. The spine is also a very complex structure with a very large number of joints, muscles and receptors, so the neurological input from the spine to the brain during core strengthening is very large.
The majority of all electrical signals generated in the body destined for the brain come from two types of receptors called muscle spindles and joint-mechano-receptors, and the majority of these receptors are located in the spine. When we exercise we stimulate the brain by moving joints and muscles. The single greatest benefit of exercise is that movement activates the brain. It increases signaling and therefore blood flow to the brain.
A joint is only as stable as the muscles supporting and moving it through its range of motion. And the firing sequence, tension and coordination of the muscles are of course entirely determined by the signals that are sent from the brain and nervous system. When we exercise to get stronger, fitter, or more skilled at performing a certain task, there are essentially two variables we are dealing with. One is the ability of a muscle to generate force which is primarily based on the size of the muscle. The other factor is the ability of the brain to coordinate the muscle activity to produce a specific movement pattern.
When we work out in a machine that guides the direction of the movement along an axis or an arc, we are primarily working to improve the size of the muscle. Since the muscle is pulling a weight along a path that is determined by the machine, there is little need for the brain to stabilize or guide the movement. There is also little need to balance the body since it is usually confined in some way. In a way we can say that since there are so few variables for the brain to be concerned with it has a tendency to become “lazy”.
As a general rule, we get good at whatever we practice. Practice makes perfect – or more correctly, practice makes permanent. If we work out with machines we get better at performing a task in that specific machine, but our increased strength may not transfer to any specific sport or skill until we practice the specific movement patterns of that sport.
Machines don’t simulate real life situations very well so while they can help us isolate and grow specific muscles, they don’t really
When we work out with free weights however; or even more so when we combine it with balancing or unstable platforms, we place much higher demands on the brain. It has to start multitasking. It is no longer enough just to contract a muscle; the brain has to relate it to all other muscles involved as well as muscles that serve as secondary stabilizers to the primary movers. As we add more variables it becomes more challenging for the brain to keep track and properly coordinate everything.
The good news is that if it is more challenging, the brain develops more and increases its capacity for coordinating complex movements while maintaining stability. This makes for greater health and fewer injuries. The greater the challenge for the brain, the greater the potential improvement in brain function unless we exceed its metabolic capacity!
That’s the caveat. The brain can get tired and burn out if we challenge it too much. Just like a muscle will develop lactic acid when we exceed its aerobe capacity, the brain will run out of fuel when it has to process more information than it can handle.
The problem is that while the muscles will tell us in very plain language, by starting to burn, when they switch from aerobic to anaerobic, the brain will suffer in complete silence. The brain does not have sensory receptors to perceive pain. During brain surgery, there is no need to anesthetize the brain tissue itself, because you can’t feel anything. Brain surgery is usually performed with the patient awake so the surgeon can check that nothing is being damaged.
Therefore you can’t feel when brain cells get tired. And while muscles are designed for high levels of lactic acid on a regular basis, and therefore have a very powerful recovery system to clean up the lactic acid after a workout or in between sets, the brain is not well equipped to deal with lactic acid. Instead it becomes toxic and the brain cell can degenerate or die.
Therefore we need to be a little more sensitive to fatigue when we do brain challenging workouts, or we may end up with injuries. When we work out with machines and challenge specific groups of muscles in an isolated fashion, the muscle will typically start burning before the brain experiences any fatigue, but when we do complex movements with great challenges for the brain to stabilize and balance the body at the same time, there is a tendency for the brain to reach its metabolic threshold before the muscles get tired.
The way that we can tell when the brain is getting tired is when we start to lose the coordination, stability, control or precision of the movement. When it doesn’t feel stable and in control anymore, we are at much greater risk of injuring ourselves.
Therefore it is much more important to pay attention to brain fatigue than muscle fatigue. Also we need to realize that when we do those types of exercises we get all or most of the benefit before we feel tired. Very often the mentality however is still “no pain – no gain” so we believe that we have to push ourselves to get significant benefit. The reality is quite the opposite; when we realize that our exercise is primarily for the benefit of the brain and we start to see how it works, we understand that very often less is more. Not only do we risk injuries with too much weight, but more weight can alter the natural movement patterns and push the body into more tense ways of doing things.
In conclusion; understand that the number one benefit of exercise is that you activate the brain, but bringing the brain to fatigue can be very unhealthy. Start within your limits. Do heavy lifting in machines and on stable platforms only after you are well conditioned. Do complex movement patterns with low weights or no weights and stop before you feel tired.
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