T Nation

Exhausting the CNS


#1

I hear the phrase in the thread title a lot, especially associated with doing deadlifts too much. I also hear it in relation to warming up; do box jumps before your workout to really fire up the CNS, etc.

I understand what the CNS is but I guess I don't really understand why deadlifting too much would 'exhaust' it more than say squatting, what exhausting it specifically means, and why box jumps 'fire' it up.

Figure I should know everything about something before I suggest the same things to a friend and not be able to answer them if they ask 'why'?

Also another question completely off topic from the title but one I don't feel merits its own thread:

My friend likes to drag me along to a 15 minute ab class every once in a while. I figured it can't hurt. I jokingly called it a 15 minute hip flexor class because that's what feels sore and that's what I feel working when I do the class. The instructor told me it's because my abs are too weak and my hip flexors are compensating. Does this sound right? The class is mostly just doing a bunch of movements (flutter kicks, holds, scissors, up / downs, etc) with the legs while holding them 6 inches off the ground.

Thanks for any help!


#2

Do you FEEL your abs get exhausted before you start feeling it in your hip flexors?


#3

the way i understand it, box jumps fire up your squat because you're able to deliver maximal force in a similar movement but without as much load as a squat. all the muscles involved then "know" how to deliver max force in the squat.

CNS exhaust (to my understanding) is when you have an excess of waste products in and around your muscles and in your synapses (the gaps between the ends of your nerves). electrical impulses might still be traveling through your nervous system, but they're unable to jump the gaps between nerves because of all the waste product that's polluting the receptors on the other end.

as for the ab class, they should slow their movements down and really feel the abs working instead of the hip flexors. then the instructor will see whose abs are really developed...


#4

I really don't feel it in my abs much at all to be honest, even when I'm concentrating on trying to contract them more. I suppose I'm doing it wrong. Sometimes in the class he'll have us do pickpockets or planks, that's the only time I feel it actually working my abs.


#5

Those are hip flexor exercises. If you want to work your abs, work your abs.

Cristian Thibaudeau once said "Complexity is the language of simple minds". Heavy deadlifts make you tired, plain and simple, and doing them too frequently will take its toll on you and your training. (See how complex my mind is?)


#6

as per the deadlift being more CNS-exhaustive than the squat, i think that's because you can't employ a stretch reflex with it like you can at the bottom of the squat (that is, if you're doing a DEAD lift like you're supposed to).