Results 1 to 9 of 9

Thread: Hitting failure because of CNS fatigue or lactic acid build up?

  1. #1
    Wannabebig Member
    Join Date
    Sep 2002
    Posts
    60

    Hitting failure because of CNS fatigue or lactic acid build up?

    This is something I've been wondering about despite lifting for some years now: Say I do really heavy sets of squats and bust out 8 reps (9th wouldn't come up if I went down) and experience no burning sensation in the quads/glutes/lower back. The set ends merely because the muscles are not able to contract under the load anymore. On the other hand I have a friend who actually starts feeling pain on a similar set and in the end has to stop (because it's too intense and the muscles can't contract).

    So the individual differences are huge. Would this example mean that I hit failure because my CNS is not able to go on, and my friend because his muscles can't function anymore? Meaning my muscles wouldn't be worked to the fullest because of suboptimal CNS performance? I remember reading something about this in Flex (yes, ) a few years ago but don't remember exactly what the final word was.

  2. #2
    Porn Star
    Join Date
    Aug 2002
    Posts
    0
    Muscle fatigue and contraction failure is more to do with ATP, or more precisely CP, and calcium depletion that just lactate build up.

  3. #3
    Wannabebig Member
    Join Date
    Sep 2002
    Posts
    60
    Yes, you are right. The title is a bit misleading. The question should probably be "Failure by CNS fatigue or depletion of energy reserves?". Still, can it be that some people have inefficient CNS and neural pathways resulting in failure BEFORE the energy reserves are depleted?

    If that were the case then people like this would benefit more from volume and not so CNS taxing training. Lots of sets and never near failure except for maybe the last one or two. On the other hand, the more neurally efficient people would benefit from HIT or low volume high intensity training as they'd get the most of their muscles in just a few sets. Any thoughts on this?

  4. #4
    3:16
    Join Date
    Jan 2001
    Posts
    4,254
    if your doing high reps with little rest between sets. its going to be far more likely to be energy reserves than a low rep set with a long rest in between.
    my exprience - joined gym 10 years ago, 6 1/2 years hard weight training exprience.

  5. #5
    Tearing **** Up FortifiedIron's Avatar
    Join Date
    Jan 2003
    Location
    Earth
    Posts
    715
    Many people believe lactic acid is what causes stiffness, soreness,pain and fatigue but they are incorrect. See lactic acid isnt a toxic by-product of the body or waste product of the metab. Lactic acid is prodcued when the body isnt as active as well. Lactate actually serve's as a very 'valuable source' of energy for the body. In the process of oxygen-independent glycolysis the pyruvate is reduced to lactate in low oxygen conditions. During Cardio activies there is enough oxygen avaliable to the cells which makes the rate of which lactic acid is produce equals its rate of removel. By this you cannot have a accumulation of lactate in the cells if it is throw out. Scientist have actually inject lactate directly into the viens or muscles fails to produce fatigue or muscle sorness, but never happen. DOM's claims cannt be claifity due to the fact that 24-36hrs after activity blood lactate reachs its normal level.



    Kc

  6. #6
    Player Hater PowerManDL's Avatar
    Join Date
    Feb 2001
    Location
    Ft. Lauderdale, FL
    Posts
    7,850
    I'd say it was pretty much acute fatigue of the muscle.

    CNS failure isn't something you'd experience during a set.
    Vin Diesel has a fever.. and the only prescription is more cowbell.

    Budiak: That girl I maced
    Budiak: macked
    Budiak: heh maced
    Budiak: I wish

    ShmrckPmp5: a good thing people can't fire guns through the computer...your ass would have been shot years ago

    Y2A 47: youre smooth as hell
    Y2A 47: thats why you get outta tickets, and into panties

    galileo: you're a fucking beast and I hate you
    galileo: hate

    assgrabbers are never subtile, they will grabb ass whereever they go,public or not, I know the type, because I am one. - Rock

  7. #7
    Senior Member Fudomyo's Avatar
    Join Date
    May 2002
    Location
    Seattle
    Posts
    0
    The difference is what kind of muscles you are using. Fast twitch, Type I muscle fibers, don't have an aerobic energy pathway. In other words they can't make lactic acid. They just stop firing. Type II muscle fibers, slow twitch, make lactic acid.

    Your buddy isn't lifting as heavy as you. He is using more slow twitch fibers, which make lactic acid once they are out of creatine phosphate.

    If you lowered the weight, you'd get more burn. If your buddy upped the weight, he'd get less burn. Your body will only fire Type I muscle fibers as a last resort, Type II are the first choice for whatever reason.

    Fudo
    Last edited by Fudomyo; 01-26-2003 at 01:07 PM.

  8. #8
    Wannabebig Member
    Join Date
    Sep 2002
    Posts
    60
    The reason I've been thinking about this is I'm kind of weak pound for pound. Not WEAK but weak for my size. I train heavy and low volume (outside light weeks and breaks) and have gained a lot of mass during my lifting career but not as much strength. I know it can't only be because of training style etc. Has to be something genetic as well. An abudance of fast twitch would mean good strength and explosiveness, however, so I have a hard time understanding where I fit in. I almost never get bad burn, even when doing higher reps. Calves, forearms and quads (somewhat) are an exception to this.

  9. #9
    Player Hater PowerManDL's Avatar
    Join Date
    Feb 2001
    Location
    Ft. Lauderdale, FL
    Posts
    7,850
    Originally posted by Fudomyo
    The difference is what kind of muscles you are using. Fast twitch, Type I muscle fibers, don't have an aerobic energy pathway. In other words they can't make lactic acid. They just stop firing. Type II muscle fibers, slow twitch, make lactic acid.

    Actually, the Type I are the slow-twitch, Type II are FT. Saying that FT fibers don't have an aerobic pathway is incorrect-- they do, but they don't tend to exploit it due to their contractile properties.

    All fibers can most certainly create lactate. In fact, the FT fibers are responsible for lactate accumulation. Lactate accumulation from ST fibers would be something not encountered during weight training.

    Your buddy isn't lifting as heavy as you. He is using more slow twitch fibers, which make lactic acid once they are out of creatine phosphate.

    ATP really. CP only serves as a reserve pool for ATP.

    If you lowered the weight, you'd get more burn. If your buddy upped the weight, he'd get less burn. Your body will only fire Type I muscle fibers as a last resort, Type II are the first choice for whatever reason.

    Its not a function of the weight so much as the duration of the movement. A longer set will become more and more endurance-oriented (obviously).

    FT fibers aren't recruited as a last resort, but rather once the force requirement exceeds a certain level.

    Originally posted by Slowmo
    The reason I've been thinking about this is I'm kind of weak pound for pound. Not WEAK but weak for my size. I train heavy and low volume (outside light weeks and breaks) and have gained a lot of mass during my lifting career but not as much strength. I know it can't only be because of training style etc. Has to be something genetic as well. An abudance of fast twitch would mean good strength and explosiveness, however, so I have a hard time understanding where I fit in. I almost never get bad burn, even when doing higher reps. Calves, forearms and quads (somewhat) are an exception to this.

    Don't constrain yourself to fiber types. Only at the highest level of competition would innate amounts of fiber types make any difference. Training over time will far outweigh any genetic predispositions to fiber types.

    Also, what do you define as "heavy" and as "high rep"?
    Vin Diesel has a fever.. and the only prescription is more cowbell.

    Budiak: That girl I maced
    Budiak: macked
    Budiak: heh maced
    Budiak: I wish

    ShmrckPmp5: a good thing people can't fire guns through the computer...your ass would have been shot years ago

    Y2A 47: youre smooth as hell
    Y2A 47: thats why you get outta tickets, and into panties

    galileo: you're a fucking beast and I hate you
    galileo: hate

    assgrabbers are never subtile, they will grabb ass whereever they go,public or not, I know the type, because I am one. - Rock

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •