T Nation

CNS Stress?


#1

What is CNS Stress? We all know what it feels like, but what causes it? Why do you get it more with barbell than with dumbell work? Is it just a matter of spinal compression?


#2

It's a component of fatigue and has very little to do with spinal compression directly. It happens that a lot of spinal compressing movements such as squat are CNS taxing due to the amount of fatigue they are capable of creating. You get more with a barbell because you are typically using heavier weights as a whole thus creating more neural stress on the body.


#3

alright, but why does heavier weight create more neural stress. any idea what physiological processes occur that leave you so drained..? maybe a deficiency in neurotransmitters inside the spinal cord after such strenuous exertion? sorta talking outta my ... right now though.


#4

A very abbreviated google search implies that it's a rather complex and not too well understood phenomenon. Here are two related (albeit somewhat old) articles that might provide some useful information:


http://www.springerlink.com/content/l01806k075214166/


#5

first link lists ammonia in the blood as one reason, from broken down muscle tissue i assume. would power lifters who use ammonia caps during a meet experience increased fatigue in the coming days? couldn't find this one on google


#6

My understanding of ammonia caps is that it isn't absorbed. Rather the ammonia stimulates epinephrine release by fight or flight. So doubt that the caps would cause any problems. Rather the heavy weights they are pounding are whats doing it. To be honest, I dont remember my physiology well enough to comment much further.

Paging Modok...


#7

certainly the crazy weight these guys push causes recovery issues, i was just curious if adding ammonia to the system would make the pain last longer, but would imagine not considering the ammonia is to trigger an adrenal response and not actually interacting with anything in the blood. I'm in first year HK and just trying to make connections, thanks for commenting.


#8

HK? Human Kinesiology?


#9

yes sir


#10

You might find these interesting.

thepursuitofstrength.blogspot.com/2011/08/powerlifting-neurology-101.html
thepursuitofstrength.blogspot.com/2011/09/powerlifting-neurology-101-smelling.html


#11

very interesting thanks.
The guy that wrote this blog seems to think that CNS fatigue doesn't exist in the way that we talk about it. i.e. i went heavy on deadlift today and fried my CNS for the next few days. but doesn't say to much about long periods of intense training that fatigue the CNS. BBB posted in a forum here (ill try to find the link) that the neurotransmitter acetylcholine can only be removed from synapse's via enzymes, but the guy in the blog says it could be reabsorbed, as well as just floating off. if BBB is right, then maybe a deficiency in the proper enzyme could cause CNS fatigue, but the whole purpose of an enzyme is to facilitate a chemical reaction without being used. so I'm not to sure about that theory.