Z1/Z2 Improvement Target: “Cardio” or Type 1 Fibers?

  • Creator
  • #46665
    Chris Beebe

    I’ve devoured TNA and have been going strong for a few months reversing over a decade of ADS and building an aerobic base. For Z1/Z2 workouts, am I right to focus on local muscle fatigue over more objective (though variable at this stage) breathing and HR metrics?

    I consider developing the aerobic system as developing ample Type I muscle fibers with the lungs and heart as secondary support mechanisms. Am I missing a physiological component that would justify keeping heart and breathing rates up even while my calves, for example, start dumping lactic acid? My understanding right now is that it’s bad to feel any sort of burn on Z1/Z2 days and that unusually low heart rates are good if it keeps breathing and, more importantly, the anaerobic burn down. Conversely, running downhill gets my HR above the HR marker for AeT, but it’s okay as long as local muscle fatigue and breathing rates still indicate sub-aerobic work levels.

    Maybe I’m overthinking it, but I’ve been really impressed with this system so far and want to make sure I understand its intent correctly. Thanks for all the resources!

  • Participant
    Dada on #46674


    Anonymous on #46724

    For Z1-2 workouts there should not be much if any local muscular fatigue unless the workouts are excessively long. What’s excessive? Long enough to cause local muscular fatigue:-)

    For these workouts and improvement in the aerobic capacity of Type 1 fibers it is best to stay in the HR zone for as much volume as you can tolerate. How much is that. Not so much that you can’t recover in 24 hours.

    Take a read through the article “Don’t Call it Cardio”. The cardiac system can’t be separated from the peripheral locomotive muscles. They are inextricably linked.


    Anonymous on #47980

    Also… 99% of proper aerobic training will have ZERO burn in the muscles. An exception might be front-pointing up low-angle ice, but in training, a muscular burn is using up fitness rather than building it.

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