From: conway@cstr.ed.ac.uk (Steve Conway)
Newsgroups: rec.bicycles
Subject: VO2 max - Terms used
Date: 26 Aug 92 16:02:11 GMT
Organization: Dept. of Linguistics, University of Edinburgh


>>ampe@cbnews.cb.att.com (john.e.ampe) writes:

[About inconsistent use of the term VO2]

>>Just express it as ml/kg of body weight/min and this way you can make
>>more direct comparisons between individuals. If you express it as ml/min,

> Yes, it is exactly because of the difference that you describe that we
> need a different name for the two quantities [ml/kg/min .v. ml/min].
>  You can draw vastly
> different conclusions depending on which value you consider.  If what
> you say is true and the medical community uses the terms
> interchangeably then I'll give up right now trying to figure out
> what the heck they're talking about.

Physiology texts use VO2 to mean ml of oxygen per minute (ml/min) and
VO2-with-a-dot-over-the-V to mean ml of O2 per kg per min (ml/kg/min).
It is very easy to miss the dot, and you can't write it in ASCII.
Maybe the discussions here should use VO2 and V.O2 with terms defined
at the start of each article ?

I haven't been following this discussion very closely, but it is
interesting that the running world seems to have recently discovered
AT training.  There have been recent discussions in rec.running and
articles in various magazines.  Noone seems to qualify the use of the
term "aerobic threshold" despite the nebulousness of the concept.

Graphs of work-rate against O2 uptake, or against lactate
concentrations look like the following (with linear portions not
included, and axes not from zero) :

O2|                        *            |
  |               *             lactate |
u |         *                     level |                  *
p |      *                              |                 *
t |    *                                |                *
a |  *                                  |              *
k | *                                   |          *
e |*                                    |*   *  
  -------------------------             -------------------------
     "work-rate"                            "work-rate"

There is no sudden threshold where you go from being aerobic to being
anaerobic, and so you must chose some arbitrary point to call the
threshold.  This can be a concentration level of lactate (blood or
muscle ?) or a measured-by-eye turn-point on the graph.  Different
people's maximum sustainable effort (race-pace) over some distance may
be at different points on the graph (higher lactate levels).

I would say that in aerobic-threshold (aka lactate-threshold)
training, we are trying to :

1. Move the lactate curve upwards, so that at any given work-rate we
are less anaerobic / producing less unused lactic acid.

2. Adapting to function better further up the curve, ie. still be able
to keep going at higher lactate levels.
--
Steve_Conway@edinburgh.ac.uk             _--_     __          0        /
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Centre for Speech Technology Research  /   _  \       \      \|     /   
and Department of Linguistics,        / __/ \  \       \ __ \/ \  _/    
Edinburgh University, Scotland.      / /     \----------/  \____|/      
Newsgroups: rec.bicycles