I am curious about the level of CNS stress caused by various types of training. I understand it is mainly intensity dependent with short sprints/plyos, however how CNS intense is a longer, slower workout like 6x400m @ 800m race pace? These types of longer tempo workouts (not used for recovery) are very intense, however i am not sure if i exactly understand the mechanism of fatigue; more from lactate than CNS would be my guess? At any rate, how much fatigue do longer reps such as SE1, SE2, int./ext. tempo cause?
CNS Recovery
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KeymasterCNS demand is a product of both volume and intensity. You can cause CNS fatigue by running only 400m if that 400m is run in the form of multiple all-out sprints. You can likewise run many miles without fatiguing the CNS as long as the pace is relatively slow. As a result, distance runners can run down their CNS just as sprinters can but because their exercise is typically far less intense (as a % of maximal effort / speed) it takes more total volume (typically in the form of miles run) to fatigue the CNS. In my opinion the best way to think of the effect various activities have on the CNS is to put them on a continuum. The more intense something is (as a % of maximal effort / speed), the lower the volume that can be done until the CNS gets fatigued. Having pointed this out, I might also say that CNS fatigue is most likely less detrimental to an endurance athlete than to a sprinter because a sprinter's performance is more closely related to the function of their nervous system.
ELITETRACK Founder
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Participant
Mike good explanation. I was going to post that earlier in different words but i knew youd be more clear.
Can you give a simple to medium explanation of the mechanism of CNS fatigue and what is actually occuring?
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Keymaster
Thanks Quik. Before I get into mechanisms of CNS fatigue, it should first be stated that acute CNS fatigue (not to be confused with Peripheral NS fatigue….which may be more of a factor in short sprint performance) and prolonged CNS fatigue likely have completely different mechanisms. The current literature is shaky and a little inconclusive regarding both types of CNS fatigue but it appears that acute CNS fatigue may be due to decreased reflex sensitivity and / or less than optimal output from the motor cortex. Prolonged CNS fatigue is likely due to increased inhibitory drive to the alpha motor neurons.
ELITETRACK Founder
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Participant
I have an issue that is related to this topic. My athletes training week goes like this. . .
Monday – Speed/MaxV
Tuesday – Ext. Tempo
Wednesday – Speed Endurance/Special Endurance
Thursday – Ext. Tempo
Friday – Speed or Pre MeetWe have over 40-50 girls on my team, so me and the head coach split them up into "varsity" and "JV". (varsity consists of roughly 13 sprinters)
For my plan, I of course use periodization training, while the head coach just kind of gives the JV girls general conditioning stuff and/or anything off the top of his head (no exaggeration).
Issue #1
This week the JV runners had a dual meet on Tuesday but he wanted to take one of my freshman varsity sprinters to the meet to run, although she was also going to be running this weekend. Now normally I wouldn't have a problem with that, but with me having my CNS day on Wednesday and not Tuesday, he threw my whole plan off. Then he was telling me he wanted her to run the 100, 200, and Long Jump at this dual meet. So because of this, this particular girl's training week will end up looking like this. . .Monday – MaxV
Tuesday – Meet
Wednesday – Special Endurance I
Thursday Ext. Tempo
Friday – Pre Meet
Saturday- MeetMy first question is, will that work, or will she be too drained to run well this weekend?
Issue #2. . .
Another athlete uses the same training week. . .Monday – Speed/MaxV
Tuesday – Ext. Tempo
Wednesday – Speed Endurance/Special Endurance
Thursday – Ext. Tempo
Friday – Speed or Pre MeetShe did everything as planned Monday thru Wednesday (MaxV, Ext. Tempo, SE1). But today (Thursday) the head coach made this runner go over hurdles at race pace (about 8-10 of them, 70-90m). He calls it speed endurance work, I call it BS. With her having to do a pre meet tomorrow and then a meet on Saturday, will SHE be able to run well in this coming meet, or will she also be drained?
ALL thoughts, questions, and comments are welcome.
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Member
Issue #1 – That girl will be fried.
Issue #2 – She should be alright. She may not set a PR, but I don't think she'll be fried necessarily. Just make sure she does nothing more than a warm up tomorrow. I wouldn't even let her do block work or anything — just warm up and go home. Make sure she stretches out well, too. She should be okay then.
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Participant
400,
1. I think she will be fried also. That's why I am gonna take her out of the meet and put someone else in her place. But what if, like I started to tell the head coach, to put her only in the Long Jump on Tuesday, and not the 100 and 200. How would that have affected her?
2. This is what I was thinking about having her doing, just warming up and going home.
Anyone else with anything to add to this?
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Member
Are plyometrics usually used during the comp. phase of training? If they are I would assume that volume would be lowered. I ask this because I have 3 important meets coming up starting with district on the 22nd, regionals 26th and state May 6th. They are all within a 2 week period and i was wondering if it would be better to cut plyometrics from my program for the sake of keeping CNS fresh? There are probably many high school runners which will face a similar scenario in the coming weeks.
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Keymaster
You can either cut out or lower the volume of the plyos to focus on pure race specific qualities, increase the intensity and decrease the volume of the plyos to enhance peaking, or address the explosive strength and elasticity normally addressed by plyos through other means (weight room, multi-throws, etc.).
ELITETRACK Founder
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Participant
When you say "race specific" qualities, what exactly do you mean? In other words, what kind of plyos would those consist of?
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Keymaster
I was referring to running when I said "race specific."
ELITETRACK Founder
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Participant
Next week is going to look like this for me:
Sunday-Rest
Monday-Plyos or Weights/Practice (Strength Work)
Tuesday-Practice (Speed Endurance)
Wednesday-Plyos
Thursday- Practice (Speed Work)
Friday-Plyos/Weights
Saturday- RestMy question is, is it required to give your cns a consecutive 2 day rest or can you rest on other days?
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Participant
That largely depends on the athlete as an individual. Some athletes may not need 48 hrs. consecutive to rest/recover from cns ++ workout(s). Others might need that larger amount of rest (this may be an athlete who isn't in great shape from a base standpoint)…or for other reasons.
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Keymaster
[i]Originally posted by marshall[/i]
Is it necessary to induce great CNS fatigue to bring about great results?I don't think anyone really knows for sure because the exact indicators of CNS fatigue are still largely unknown. At the very least though, I think it's safe to say that the CNS (or any other system for that matter) has to undergo a sufficient amount of stress to result in a supercompensation effect. I would likewise imagine that this stress would almost certainly need to be enough to produce acute CNS fatigue. I don't think chronic CNS fatigue is necessary though and should it occur it would probably be best to use it as a warning signal to back off the training.
ELITETRACK Founder
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Participant
"I don't think anyone really knows for sure because the exact indicators of CNS fatigue are still largely unknown. " – mike
what IS known as an indicator of CNS fatigue?
drop off in performance, herat rate fluctuations, body temperature,
other symptoms that are overtraining symptoms would fit?
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ParticipantI like tonus….and coordination ….and hamstring PNF….and feelings.
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Keymaster
[i]Originally posted by marshall[/i]
"I don't think anyone really knows for sure because the exact indicators of CNS fatigue are still largely unknown. " – mikewhat IS known as an indicator of CNS fatigue?
drop off in performance, herat rate fluctuations, body temperature,
other symptoms that are overtraining symptoms would fit?
Drop off in performance isn't the best indicator of CNS fatigue because by the time it happens it might be too late to do anything. Also, motivational state which may or may not be linked to CNS state may effect these results. HR fluctuations and resting morning HR have been used but there could be other factors which could cloud the issue here on this one. Interesting, if I recall correctly it isn't HR fluctuations that signal CNS overload but actually the lack of HR variability meaning the more exactly similar the time duration for each beat, the more likely CNS fatigue has occured. As for body temp, their are likewise other variables which could cloud the picture. Perhaps the best method and one which I discuss in the article I am in the process of writing (the same article I mentioned a while back on biodynamical periodization) is one which is more all-encompassing including subjective, objective, quantitative and qualitative measures rather than relying on single indicators alone.
ELITETRACK Founder
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Participant
cant wait for this article mike!
There is also performance on simple coordination or power tests, I remember from Kurz's science of sports training that tests like vertical jump, broad jump, spinning as much as possibly in one jump, could possibly be used.
what do you think about those?
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Keymaster
I like all of those tests but if you use it as the only indicator you'll soon find that it's far from fool proof as thing like motivation, warmup, and learning effect can all result in deviations in performance not indicative of CNS state.
ELITETRACK Founder
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Member
Need your help guys, I have state meet on May 6 (Thursday) at LSU and was wondering how i should taper for it. I would like to get one more speed endurance/plyo session and maybe a SE 1 workout in as well. Heres what I was thinking.
Wed. – Regionals 400 and 4×400
Thurs. – Light GS/ Off
Fri. – Plyos (low volume) + 4x100m w/ 5-7 min. + Weights (low voulme)
Sat. – Light GS/ Off
Sun. – SE1 2x300m
Mon. – Light GS/ Off
Tue. – Warm up/ Strides
Wed. – Full Warm up
Thu. – STATE @ LSU -
Keymaster
Are the 4 x 100m hard? If so, I think it looks pretty good but I'd probably add some flying sprints (something like 3-4 x 15m w/ 3' rest) on the Tuesday prior to the meet. If this doesn't answer your question or you'd like to discuss further let's start another thread. Good luck at LSU, if you see me say hi.
ELITETRACK Founder
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