From: scott@eggneb.astro.ucla.edu (scott evans)
Newsgroups: rec.bicycles
Subject: Re: VO2 max (was Re: Heart Rate Survey: Results)
Date: 26 Aug 92 00:25:31 GMT
Organization: UCLA Dept of Astronomy

In article <1992Aug24.223426.17246@hpcvusn.cv.hp.com> harry@cv.hp.com (Harry Phinney) writes:
>seasons and set the world hour record.  I'd say if he can improve his
>power output at AT, then most of us can as well.
>
Careful...Improving one's power output at AT is quite different than
improving the actual AT as a percentage of max.

scott@eggneb writes:
>: The idea of training is to improve both your VO2 max and your AT as a
>: percentage of max.
>
>This all depends on what attributes one is trying to improve through
>training.

Sorry that I wasn't specific. I'm referring to training for the purpose
of racing where one wants to have high power at AT and have a high AT as
a percentage of max.
>
>: Now, as for your ability to go 180 for a long time,
>: I should mention yet another zone of output. There is a zone just after
>: the AT and  only a few heart beats per minute in width where you will
>: produce lactic acid but your body will still be stable under the load
>: for long periods of time.
>
>This depends heaviliy on the individual.  The AT is clinically defined
>as a certain blood concentration of lactic acid.  Some individuals can
>sustain efforts above this concentration and others cannot.  Training
>can most likely improve this ability.
>

In the UCLA study, the term "fatigue thresshold" was used. I've naively
substituted AT for this value. Specifically, the FT is the point where
the VCO2 increases faster than the VO2. The idea here is that the onset
of anaerobic muscle use creates excess CO2 as well as lactic acid.  That
is, the increased CO2 output is an indicator of anaerobic work.

>: Above that level, the lactic acid in your
>: muscles will eventually lead to exhaustion.  Thus, when you ride a TT,
>: you don't want to be aerobic (for a long TT) the whole time but, rather,
>: you want to work in the zone where you produce lactic acid but not at a
>: runaway rate.
>
>One is always producing lactic acid.  Lactic acid is a natural byproduct
>of some of the metabolic processes, and is used as "fuel" for other
>metabolic processes.  The acumulation of lactic acid at exercise levels
>above the AT is due to chemical reaction rate and capacity limits.  The
>processes producing lactic acid are outrunning those consuming lactic
>acid.  For a TT, one wants to ride at their non-clinical AT, that is,
>the maximum effort level that one can sustain for the duration of the
>event.  (i.e.  As fast as you can go for that distance, duh...).
>
right. Again, I was using a simplistic interpretation where "lactic acid
production" means production faster than you can get rid of it.

>: Lastly,in a study done at UCLA, it was found that in the runaway lactic
>: acid regime, you can work as a function of time in a HYPERBOLIC manner.
>: That is, if you plot work on one axis and time on another, the curve
>: will be a hyperbola, asymptotically approaching your AT power output at
>: time equals infinity.
>
>I would expect this to be true only if one does not go too far beyond AT
>at the beginning of the time period.  Dr. Jansenn's book
>_Training_Lactate_Pulse_Rate_ has some good examples of athletes who
>exceed their AT early in a TT-like effort and whose pace late in the
>event suffers tremendously.  Most of the more successful examples in
>his book start at or slightly below their AT, and only significantly
>exceed it toward the end of the event.
>
Very true. If lactic acid is in your body, your muscles work much less
efficiently.
>Harry Phinney   harry@hp-pcd.cv.hp.com

Scott Evans
UCLA Cycling