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Scourge_of_God
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2004/01/03 18:49:54 (permalink)

CNS

Can someone please explain to me the biology behind overtraining the CNS? What are the symptoms of this occuring? How can this be avoided, except by sleeping lots?
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    Robert
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    RE: CNS 2004/01/04 12:40:07 (permalink)
    this must be the sole topic in the history of MT where no-one knows jack about the subject... shame.

    google is your bet bet scourge. although i got to page 15 of search results before i found anything useful... by that time i was nearly asleep. or try a book at library.
    rob
    #2
    Scourge_of_God
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    RE: CNS 2004/01/04 14:25:13 (permalink)
    I haven't defeated MT, have I?
    #3
    Big-AL
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    RE: CNS 2004/01/04 14:28:49 (permalink)
    Possibly, it is a big question, the ultimate answers seem quite simple, as you said sleep, but the biology etc behind it and the details, well that could surely fill a book!

    AL
    #4
    Dildo69
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    RE: CNS 2004/01/04 14:54:33 (permalink)
    Its just plain hard learning about this! But im gonna keep trying!
    #5
    drab4
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    RE: CNS 2004/01/04 15:26:52 (permalink)
    What IS overtraining of the CNS?

    I've not heard of this before. How is it possible? The only way I can think of would be to damage the nerves, this cannot happen in a workout unless you injure yourself, as far as I understand. Healthy nerves do not fatigue to any great extent, so the muscles would be overtrained 10 times over before the CNS got bothered.....

    That's my guess anyway, like I said I've never heard of this type of phenomenon before, except in cases of ill people with multiple sclerosis and similar diseases.
    #6
    drab4
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    RE: CNS 2004/01/04 15:34:22 (permalink)
    Or perhaps I have misunderstood entirely...... Is overtraining of the CNS a reference to the brain's normal response to muscle fatigue?

    Of course we know that if extreme muscle fatigue is "detected" by the brain, there is some inhibition of voluntary effort. So the fatigue becomes GREATER than simply muscle fatigue, it also becomes more difficult to control that muscle.

    Though I wouldn't personally call that overtraining the CNS, as such. Anyway, I'll let someone who's actually heard of this before answer lol.
    #7
    Dr Helium
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    RE: CNS 2004/01/04 15:34:43 (permalink)
    This seems like a pretty good explanation. The entire article can be found at:

    http://www.protraineronline.com/past/june1/restandrecovery2.cfm

    Neuromuscular Fatigue

    Neuromuscular fatigue is associated with central nervous system (CNS) and its ability to communicate with motor units within a muscle. It can be divided into two types: high-frequency and low-frequency fatigue. High-frequency fatigue is usually associated with activities that last around 60-seconds or less. This type occurs as a result of potassium build-up in key places within the muscle fibers, which interferes with the electrical signals that cause muscular contractions. Force output decreases because of this decreased ability of the muscle cells to conduct the electrical signals across the cell membrane. Cold-muscles are more vulnerable to this type of fatigue than warm ones are, making a proper warm-up a very good idea.

    Low-frequency fatigue is associated with cellular damage, particularly the damage caused by eccentric contractions. This cellular damage can leave the portions of the muscle fibers that conduct the electrical signals literally torn and frayed. This too will obviously have an effect on force output. Failure to allow the muscle fibers to repair themselves and reestablish an optimal connection with the CNS (best accomplished by alternating periods of high and low intensities) will result in those same muscle fibers eventually being placed in a state of inhibition to protect them from further damage. This means that muscle contractions will be noticeably slower and weaker.


    #8
    Boxer
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    RE: CNS 2004/01/04 15:46:28 (permalink)
    Also, the cns is so complicated I bet a neurologist would have a hard time describing overtraining.
    #9
    Scourge_of_God
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    RE: CNS 2004/01/04 17:21:48 (permalink)
    quote:
    Originally posted by drab4

    What IS overtraining of the CNS?

    I've not heard of this before. How is it possible? The only way I can think of would be to damage the nerves, this cannot happen in a workout unless you injure yourself, as far as I understand. Healthy nerves do not fatigue to any great extent, so the muscles would be overtrained 10 times over before the CNS got bothered.....

    That's my guess anyway, like I said I've never heard of this type of phenomenon before, except in cases of ill people with multiple sclerosis and similar diseases.


    Well... This is part of my problem. Unless I've misunderstood them, I've seen lots of people use this to explain why you can't continually do 1RM for every session or why you can't do x much volume etc., but I've got no idea what it is? I can understand how muscular fatigue/damage will play an issue in preventing you doing these things, but the CNS thing keeps coming up as well as differentiated from the effects on the muscles. Doc Helium's post seems to suggest that the two are related.
    #10
    Squat600
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    RE: CNS 2004/01/05 10:40:59 (permalink)
    CNS burnout is when you use weights approaching a 1 rep max and consistently over-psyche for a lift, or train to or past the failure point on a regular basis (especially with heavy wights). This causes the central nervous system to enter a state of inhibition in which it cannot/will not recruit the muscles to produce maximum force. Continuing to push hard on the same, or very similar, lifts in that condition causes the CNS to become more inhibited - precipitating a case of overtraining.

    Whether CNS inhibition is a result of "less responsive" muscle cells (due to increased firing thresholds within the muscle fibers themselves), muscle spindle feedback being diminished, golgi tendon organs becoming overly sensitive, inhibition due to proprioceptors in the joint capsules, the peripheral neurons or the central nervous system itself, the remaining fact is that hard training along the same lines that caused the condition cannot continue in this state. The only solutions are rest and change.

    You can't give it your all everytime you train, for extended periods of time. Eventually the body needs a break and a change in stimulus.

    #11
    GTM
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    RE: CNS 2004/01/05 12:55:30 (permalink)
    Squat..

    Whilst the answer to the problem remains the same.. ie rest and recouperation. If the article posted above is true.. and most of the reasons you propose yourself.. then then CNS overtraining is a misnomer. The actual nervous system itself isn't directly affected..just the muscles ability to respond to it.

    IMHO.. for CNS overtraining to be a true phenomenom would require the actual CNS to have it's ability to transmit motorneuron signals to the muscles to have been diminished.. either due to a non-ideal chemical condition within the neural cells themselves or due to the brain reducing the stimulus, in response to feedback from the muscles. Even the latter wouldn't IMHO be true CNS overtraining as it's just a response to the state of the muscles not the actual nervous system itself.

    Like has been stated above..to the best of my knowledge at least.. true reductions in the ability of the CNS to function correctly are only due to motorneuron conditions such as MS etc.

    GTM
    #12
    Robert
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    RE: CNS 2004/01/05 16:14:04 (permalink)
    no-one here even trains the CNS anyway, CNS=brain+spinal cord

    its the PNS thats in question...

    i think it has something to do with a buildup of either [+] or [-] ions [whihever is the waste product in message transmission along axons/nerons blocking the next message getting through.

    my understanding is this.

    having gone to my local waterstones and thumbed through many a medical text in the vain hope of something relevant i found this out...

    there will be many nerves that supply a motor unit [a single muscle fibre or collection of them] these motor units only make the muscle [or part of it] contract or polarize its ions in cells to contract if the whole* of the nerve supply to that motor unit says so. its an all or nothing kind of thing, if there are 8 nerves that suply it and 6 say contract then it will, if only 2-4do then it wont.

    it said little more than go on to explain that a biuldup of the wrong kind of ions [calcium i think] will inhibit the transmission of these messages to contract the muscle.

    i therefore presume that:

    more wieght used on a lift=more muscle fibre recriutment, this therefore=more messages are transmitted accross PNS.
    the more messages transmitted accros PNS=more chance of ion build up in neurons/axons [cannot remember which part of nerve]=more buildup=less chance of getting a majority vote if you like for the muscle to conract at previous intensity/frequency/force. hence over training.

    and drab is right, nerves CANNOT grow/expand network, all they can do is get better at what they do by streamlining. [a bit like what your brain does during REM sleep, and is belived to be the cause of dreams, but thats another story...]

    hope that helps/is accurate.
    rob

    thoughts??
    rob

    #13
    Scourge_of_God
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    RE: CNS 2004/01/07 01:53:58 (permalink)
    Wow... University of MT. Neurology 401.

    This is making a lot more sense than it did earlier... Thanks y'all.

    An interesting follow-up to this, assuming our understanding is correct, would be to work out the mechanism by which the body clears the build-up of spent neurotransmitter ions. If you knew how this works, and the things it relies on to make it work efficiently, you would have a number of other things you could do to prevent overtraining and increase recovery, in addition to copious R&R.

    Does anyone know where to find the resources you would need to work this out? Or am I just going to have to hassle some med students?
    #14
    acooper
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    RE: CNS 2004/01/07 12:18:50 (permalink)
    Okay i just had to sign up and reply to this thread on the CNS. The posts so far have had a go at describing the pysiology behind the CNS but here are the facts.

    The CNS is required and must be fully recovered for any power/ strength training, that's any lifts <6reps and any fast reps like oly's and plyometrics. Being power and strngth athletes you must be aware of the CNS and its role if you are to train effectivly.

    For the CNS to function effectivly the following conditions are required:

    [1) The CNS has to be fully regenerated so that the chemical environment required for optimal transmission of nervous signals is intact. 2) Motor pathways required for efficient routing of motor signals must be in place.

    You need to understand the difference between CNS fatigue and residual muscle fatigue. CNS fatigue is reached when the by-products of high intensity excercise build up to the point where the CNS impulses necessary to voluntarily contract muscle fibre are handicapped](ref1)

    The CNS needs at least 48hrs recovery (thats the absolute minimum) before another power/strength session. That limits you to 3 session a week of CNS work. To aid recovery the following methods can be used:

    Contrast Showers: alternating hot and cold water onto the base of the skull at the back of the head; 3min hot, 1min cold, 3min hot, 1min cold, 3min hot, 1min cold. Massage, and Calcium supplementation. Plus at least 9hrs sleep a night.

    Symptoms of overtraining are:

    * Loss of performance
    * Muscle shakes
    * Loss of concentration
    * Cramps
    * Trouble Sleeping.

    CNS fatigue will result from 1) doing sessions that impact the CNS to frequently. 2) to high a volume of CNS excercises in a session.

    To help you to be able to budget your CNS work here are some general rules of thumb:

    * The higher the weight the higher the stress
    * Lower reps resulting form heavier weights and/or faster reps will increase stress
    * Attempting a pb or a heavy lift will increase stress form psycing up.
    * The higher the speed the higher the stress.

    Here are some tips regardng various excercises:

    The most stressful lift is the deadlift. Stress can be reduced by using a snatch grip or by standing on a raised platform. This will reduce the load on the upper part of the lift and hence the total stress.

    Next the squat. Stress can be reduced by using front squats and/or if you're going to parallel going deeper to full squats.

    Oly lifts. apart from the speed the biggest stress comes from the psycology of the lift. I would therefore suggest using buffering which will ensure you are lifting weights you know you can complete. The principle of buffering is to lift in 4 week cycles at a % of max with the forth week an unloading/recovery week where intensity and volume are decreased:(this can be adopted for all lifts)

    wk1 - 90% 'X'RM
    wk2 - 95% 'X'RM
    wk3 - 100% 'X'RM
    wk4 - unloading week

    That's my input. If you want more information you should log onto the forum at CharlieFrancis.com where CNS based strength training is discussed in great detail.

    Alan.

    ref1 pg29 Charlie Francis Training System.

    #15
    Boxer
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    RE: CNS 2004/01/07 13:37:06 (permalink)
    Welcome to the site Acooper.

    Good post but I disagree with this statement "The CNS needs at least 48hrs recovery (thats the absolute minimum) before another power/strength session".

    Many of the strong men of old used to train every day and also a modern guru that I can think of that advocates training every day for strength is Pavel Tsatsouline.
    #16
    acooper
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    RE: CNS 2004/01/07 14:11:25 (permalink)
    "Good post but I disagree with this statement "The CNS needs at least 48hrs recovery (thats the absolute minimum) before another power/strength session"."

    Perhaps i should have written power/max. strength sessions. If one requires to train more regularly then other sessions can be used in the days between CNS impact days but with higher reps >12 and at a controlled speed. i.e.

    m - CNS low reps
    t - High Reps
    w - CNS low reps
    t - High Reps
    f - CNS low reps
    s - High Reps
    S - rest

    As the CNS' function is required for heavy/max. lifts and in competition its ability to function properly is very important. High rep sessions would increase muscle capilarization which will improve blood flow and heat in the muscles both of which will improve CNS function when it is needed. These sessions can be done without impacting the CNS whilst allowing the addintional sessions.

    #17
    drab4
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    RE: CNS 2004/01/07 15:58:50 (permalink)
    Interesting posts everyone..... Looks like lots of people have heard of this phenomenon before (unlike me).

    Anyone want to have a go at this part of SOG's original question
    quote:
    Can someone please explain to me the biology behind overtraining the CNS?
    In a bit more detail? We've had some varying background info, but would someone like to explain the processes involved?
    #18
    acooper
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    RE: CNS 2004/01/07 16:57:21 (permalink)
    Here's a link that expands on Dr Heliums post a bit

    http://www.engr.mun.ca/~butt/physiology/fatigue.html

    And here is an extract regarding the CNS

    Central Nervous System Fatigue
    In order for a muscle fiber to twitch the central nervous system (CNS) must send a nerve impulse to the controlling motor unit. The innervating nerve cannot maintain its capacity to transmit this signal, with optimum frequency, speed and power for extended periods of time. Eventually concentrations of substrates such as sodium, potassium, calcium, neurotransmitters, enzymes, etc. decreases to the point where muscle contraction becomes markedly slower and weaker. If high discharge rates are continued the nerve cell will assume a state of inhibition to protect itself from further stimuli. The force of contraction, therefore, is directly related to the frequency, speed and power of the electrical 'signal' sent by the CNS.

    Interestingly, though far from understood, is the fact that a trainee's motivation and emotional state can profoundly affect the discharge characteristics of the central nervous system.

    Clearly, the central nervous system can play a pivotal role in the perception and reality of fatigue.

    #19
    GTM
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    RE: CNS 2004/01/09 23:13:28 (permalink)
    quote:
    Originally posted by acooper

    Here's a link that expands on Dr Heliums post a bit

    http://www.engr.mun.ca/~butt/physiology/fatigue.html

    And here is an extract regarding the CNS

    Central Nervous System Fatigue
    In order for a muscle fiber to twitch the central nervous system (CNS) must send a nerve impulse to the controlling motor unit. The innervating nerve cannot maintain its capacity to transmit this signal, with optimum frequency, speed and power for extended periods of time. Eventually concentrations of substrates such as sodium, potassium, calcium, neurotransmitters, enzymes, etc. decreases to the point where muscle contraction becomes markedly slower and weaker. If high discharge rates are continued the nerve cell will assume a state of inhibition to protect itself from further stimuli. The force of contraction, therefore, is directly related to the frequency, speed and power of the electrical 'signal' sent by the CNS.

    Interestingly, though far from understood, is the fact that a trainee's motivation and emotional state can profoundly affect the discharge characteristics of the central nervous system.

    Clearly, the central nervous system can play a pivotal role in the perception and reality of fatigue.





    Perfect... so it would seem that CNS "overtraining" would constitute a chemical environment that is not conducive to 100% efficiency of the CNS to transport the signals required to create maximal muscle contraction (assuming the muscles themselves are capable).

    Makes sense to me.

    GTM
    #20
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