From: harry@cv.hp.com (Harry Phinney)
Subject: Re: VO2 max
Organization: Hewlett-Packard Company, Corvallis, Oregon USA
X-Newsreader: Tin 1.1 PL4
Date: Tue, 1 Sep 1992 00:32:16 GMT


praetzel@marconi.uwaterloo.ca (Eric Praetzel) writes:
:   VO2 max is tested.

This is true.

: The test is between 10 and 30 min.
: depending upon how quickly they want to get it over and depending upon what they
: actually want to get from the data.

Which is one source of variances in tests.  Different testing protocols
(e.g. "how quickly the want to get it over") will result in different
numbers.

: My text book basically mentions some
: precautions for older unfit people but generally you will hit your VO2 max
: before you hit your max power and max pulse.

Correct.  The VO2max point is the effort level where the aerobic
metabolisms are putting out their maximum power.  The anaerobic
carbohydrate metabolism will also be putting out quite a bit of power at
this point (i.e.  you're beyond AT), but is not generally at its
maximum.  This also tells you nothing about how much power one can
produce from the alactic anaerobic mechanism (ATP/CP), which is one
of the targets of the Wingate test.

:   I want to push genetics some more.  VO2 max is usefull as an indicator of
: your absolute max potential.

If one is forced to go beyond AT, it matters little whether they must go
to VO2max, or beyond.  It is (in my opinion) unclear just how much
VO2max can be affected through training.  Most sources cite relatively
short term studies and conclude that the average person can only
increase their VO2max by maybe 15%.  On the other hand, Pete Penseyres
has been having a test done at least once a year for the last 9 or 10
years.  Each test has shown an increase.  It is quite possible (again,
IMO) that this is a normal outcome of a well planned and executed
training program, but it is also possible that he's learning to take the
test.

: But again how close you can get to it depends a
: lot on training and also upon genetics.  There was one runner who could
: apparently maintain 98% of his VO2 max but generally olympic and pro caliber
: people will sustain 85% to 90%.

Right, which is one of the primary reasons the VO2max is not a good
predictor of athletic performance.  The athlete's power output at AT is
a much better predictor, and appears to be much more trainable than
VO2max.

: If you look at your power
: output for a given oxygen comsumption you can guage your efficiency.  That is
: done by treating the human body as an engine, assuming that you are buring
: basically fat and that all power generation is aerobic.

These are a couple of pretty big assumptions.  Even at relatively low
power levels the aerobic carbohydrate metabolism is producing
significant power, and by the time AT is reached it is likely dominant.
Again, by the point of VO2max, the anaerobic metabolism will be heavily
engaged.

: If your efficiency is low like mine (21%) you are not in danger
: of becoming a Cat 1 or 2 or 3.

Unless you have access to a lot more data, I don't think you can conclude
this.

: Perhaps the efficiency is trainable but it seems very unlikely.

Why?  It seems that technique could affect this significantly.

: Another
: consequence of this is energy used.  Even if just touring I will use 30% more
: energy than him and will have to eat and drink more (this has become very clear
: to me when my friends are along).

If you are having to eat more during rides, then I would say that your
fat metabolism is under trained.  You are relying more heavily on the
aerobic carbohydrate metabolism than are your friends.  Some coaches
(e.g.  Sleamaker, me) believe that the fat metabolism is best trained by
long, steady paced rides at a relatively low intensity.  Some (e.g.
Mike Walden) even believe that doing more intense training before the
fat metabolism is properly prepared will limit further development of
the fat metabolism (I personally doubt this).

Harry Phinney   harry@hp-pcd.cv.hp.com