I think that we all undestand concepts of CNS stress and fatigue during >95% velocity, but is there any real scientifical proof of this? Measurement of muscle twitch, H-reflex, M-wave, MVC, low freq stim, high freq stim, isokinetics before and after speed session?
How do the CNS fatigue theory “interact” with central governor model of Tim Noakes?
The only real way to measure CNS fatigue is through the Omegawave system I think. I am unclear as to how it works though.
Do a search on the work of prof schmidtbliecher et al.
Brain commands, brain protects; everything!
good point…I think the CNS shuts down to prevent internal overload of tendons.
Why tendons?..
Whether biological or not, a battery needs to be recharged or produce/convert new bio-chemicals (in this case neurotransmitters etc.). I’m not sure if the CNS shut down is due to tendon protection; that would basically imply a signal sent from the tendons to the brain when fatigue begins. Although, it could, indirectly mean that tendons are protected as a consequence of CNS shut down, but only among other things.
I do not agree here: one specific assessment provided by the Omegawave system monitors CNS potential (in millivolts),giving a momentary picture of the functional state of CNS. It is done with a very simple,non invasive protocol lasting only a few minutes,with the subject at rest.
After personal use over time of the system,I think that what we all refer to as “CNS fatigue” or “CNS fatigue theory” is a much more complex definition,hard to identify with a single millivolts potential index and which involves consideration of Autonomous Nervous System (ANS) as well as Muscular System based phenomena .
For this very complexity I would say the comparison between CNS fatigue and central governor theories is most appropriate and very interesting,as it might truly provide new directions in our discussions here,helping better further analysis and comprehension of both.
By the way: either ANS and Muscular System can be quite affordably monitored by the same technology,but this is a whole different story beyond the purposes of discussion here.
The only way to measure CNS fatigue (after all what is fatigue, and can we measuer it?) is to measure performance with and without artifical stimulation (EMS, see Enoka, Neuromechanics of human movement), and according to same difference to evaluate fatigue (in some %)…
According to Central Governor Model (Noakes et al), fatigue is relative emotional representation of effort that system (CNS-central governor) makes to maintain homoeostatics (homeostasis), thus preventing “catastrophe” leading to injury and maybe death!
This doesnt mean that there is no negative influence of “poisoning” metabolites on muscle contraction, neural conduction etc, but this model suggest that their influence is controled by shuting down the system before their concentration reaches critical limit - “catastrophe” running out of homoeostasis!
The key evidence for this is that neural activation of muscles during fatigue is not maximal (as other “catastrophe” model propose, like cardiovascular/anaerobic model) but less than maximal, even come to 30%…
So the key question is:
Is CNS fatigue an inability of Neural Drive (CNS) to fire impulses or he is not willing to do it (to maintain homoeostasis, and system functioning)?
After sprinting there is lower CP concentration (not ATP) in muscle cells and lower PH of cells, so this maybe induce Neural Drive inhibition, wich we see as CNS fatigue! According to literature, to return Ph to normal is needed for about 20-30min, so this is the key proof for Charlies long rest between sets and reps…
Yes, on the other hand there is some “metabolic” build up in the CNS and neurotransmiter lack, but is this a real reason for inability of Neural Drive to fire, or according to Central Governonr Model, some inhibitory-protection to maintain homoeostasis in the brain itself by inhibiting Neural drive by some inhibitory impulses… I think there is the need to connect and integrate Bernsteins MotorControler (wich is hierarchical, redundant, use feed-back and feed-forward mechanisms) with Central Governor, as a goal of CNS to produce movements but within limits of maintaining homoeostasis (in healthy humans)! I think we cannot use reductionism here… its like that story of blind men and elephant proposed in one of the Noakes papers (wich is a must read)!
I dont think that Central Governor shuts down Neural drive to muscles to protect tendons! If this is the case then eccentric contraction would produce same force as isometric (in vivo)! So this is not the case here, or maybe is but the system is not perfect yet, we are still evoluting…
This is a complex situation which may lead to confusion. The arguement against the long term CNS fatigue as I describe it (long after the effort, perhaps days or even more) is the classical definition, which is the protective mechanism that prevents damage or death to predators (during the effort, leading them to stop, allowing them to live to fight another day).
Of course, there’s no point stopping if you’re the prey. Just as well to die of a heart attack as to be torn apart by a pack of wild dogs!
Some kind of equipment must be used for “CNS fatigue” detection/prevention well before this is realised in performance; it’s too late by then… Therefore, I support CNS monitoring with, but not without equipment, e.g., via a field test… If the latter is the case, I don’t want to know! 
As pakewi says, OW gives a pretty good picture/idea of what’s going on with this complex issue and this is my understanding as well -after a demo only; whether this is the only answer, or not, I don’t know… It’s better than nothing though!! :rolleyes:
Just heard about a strength coach who, when discussing his approach to training in a classroom setting, used the expression “fry your nervous system.” Someone stopped him short and said,“what the heck does that mean?” He didn’t have a good answer. The instructor of the class added “there’s really not much proof of that.” As a strength coach/former sprint coach, I get where he’s coming from but I’m curious to know how members here might have answered?
Not sure you can say OW prevents CNS fatigue on its own. It can see it after and keep it from getting worse before the next session. There’s no substitute for good forward planning and clear observation DURING training to adjust as needed. That said, OW is a great tool!
Charlie,
I remember in the Jane Project that you mentioned that Jane had a good potential for high intensity demands when tested by the OW. A couple of questions then.
- Could this be considered a talent identification tool? (this could have the potential to be a huge impact on high intensity sports)
2a. How do you think the CNS capacity changes during adolescence?
2b. How much can this capacity change during adolescence? (I pretty sure that this answer would be better answered by the “Organism Strength” thread)
- If you could … it would be VERY interesting to see how Ben and Angela would test now for capacity. hint hint … nudge nudge
I could be- or it may also be an indication that strength levels (the stressor for the CNS) is not up to the challenge. Tough to say with certainty, but, if strength levels are pretty decent and you see this response, it would be pretty convincing. but I’m always worried about early talent ID methods that may throw the baby out with the bathwater
Personally, I think that talent ID (with the obvious screeners already done) would be done only until adolesence is finished. Males 18-20 Females 16-18 (just my thoughts) So, I wouldn’t be getting rid of any potential talents too early. The unfortunate exception “Fudgie” (a 200lb 4’-10" 13 yr old) who during adolesence undertook speed training to 30m only and did a major strength training program and then at age 20 did the zone diet program while maintaining strength levels and increased his alactic speed volume and training distance to <60m all the meanwhile growing to 5’-10" 165lb man.
What about question 2? Any ideas?
Question two is so variable that I don’t think there is a valid overall answer
Charlie’s words make the whole point (no surprise…): I might only add I just had the chance to see the most recent developments of the technology features and they most interestingly correlate CNS potential assessment with precise indications about adequate momentary training prescription.I am now extremely curious to explore how numbers and waves of stimulation fit different individual athletes.