From: praetzel@marconi.uwaterloo.ca (Eric Praetzel)
Subject: Re: Aerobic Capacity
Organization: University of Waterloo
Date: Fri, 8 Jan 1993 13:41:47 GMT

Round 2:

In article <1993Jan8.012411.24566@nosc.mil> derion@VAX309.NOSC.MIL writes:
>In article <C0I7J4.7pn@watserv1.uwaterloo.ca>, praetzel@sunee.uwaterloo.ca (Eric Praetzel) writes:
>>  I have gotten data from people who had no such deflection point.
>>I propose a standard.  Ie your "AT" is defined as what you can sustain for
>>1 hour.  
>
>Anaerobic threshold is simply the point at which the relationship between
>V'E (ventilation) and V'O2 deviates from linearity.  It couldn't be
  Pretty well every chart I have seen shows a break in the plot.  It is
usually going from one slope to a higher slope.  The AT tends to be at about
75% to 90% of V'O2 max while the VT (ventricle threshold) that you mention
is at about 60% of V'O2 max.

>Your measure of "fitness" is the ratio of your V'O2 at the AT and
>>your V' O2 max.
> 
>V'O2 max will increase with training, and you will reach your
>anaerobic threshold at a higher % of your max with training.
>I'm not sure what that ratio would tell you.
  Some people will be able to shift their AT point higher up the V'O2 vs
power curve but generally the heart rate at the AT seems to decrease with
increases in fitness.  Since people vary so wildly in the AT as a percentag
of VO2 max I am hopefull that a ratio of the two would give a better indicator
of how "trained" a person is.


>> A high V'O2 max guarantees you nothing. 
>
> Not true!  For example, you'll have a lower heart rate at the
>same submaximal V'O2 if you're trained vs untrained.
  Basically I am bucking the main stream because it is not uncommon to see
a large variance in the V'O2 max.  Pro cyclists will tend to be between
65 and 80 ml/m/kg.  Runners can vary even more because their "efficency"
is much more dependant upon technique.
  We have a case where it is typical to see 25% differences in V'O2 max,
amoung an elite group.  I am not sure what sort of differences there are
in the efficiency.  Norms for students is apparently 21% +/- 6%.  Amoung
pro's I am sure that you will see 20% variances.  So it is not uncommon
to see someone with a "low" V'O2 max and a high efficiency amoung the elite.
That is why I hesitate to use the V'O2 max as an indicator of anything.


>I don't understand what you mean by "better".  I would think having
>a higher V'O2 max on a cycle than one's opponents would certainly be
>an advantage.  And at a GIVEN submaximal workload, unless you're an
  As I typed that I thought it over.  A higher V'O2 max is not what you
want.  What you need is to have a higher "reserve" in your V'O2.  ie you
want more available energy between your current V'O2 and your V'O2 max.
Again that is why I prefer to think in terms of a ratio of V'O2 to V'O2 max
instead of absolute values.  It is roughly simular to just the V'O2.
  If you express V'O2 as ml/kg/min they you are adding in the persons mass.
But their fat mass can change although their V'O2 (in L/min) will not but
the V'O2 in ml/kg/min will.  Each form will work under certain cases.
  But generally the absolute V'O2 is the only indicator to use for one person
while ml/kg/min is a better one when dealing with group comparisons.

>> You may be interested to know that my V'O2 max does not change between the
>>summer (and my height (?) of fitness) and january.  Perhaps this can be
>
>It most certainly can change with training!!!  Improvements in V'O2
>max usually range from 6-20% depending upon initial fitness level.
  Yes it can.  Some people can keep increasing theirs for 3 or 4 years.  But
when I consider that I will need a 30% improvment to keep up with my friends
I am not hopefull because I see no changes over 5,000 km of training.  Each
person is different.  Recent studies have shown that some people respond
amazingly to training while others do not. Unfortunately I have not found
paper copies of those beause I am curious to see what sort of people they
used.
  After looking at a bunch of data I am of the opinion that a fit person
could do a summer of training and have a good idea of what calibre he is.  In
my case I have seen no improvements even compared to my first year which had
only 1,500 km of riding (compared to 10,000 km this year).  Yes there are large
differences in endurance but for the 15 km TT (our clubs short course, out and
back on flat sheltered ground) I can't see anything.  As encouragement all that
I can say is if you have it you will keep it. I get my ass kicked weekly by
50 year olds that are still doing 40km in 57 min to my 1-07.
  If anyone is interested there is a program called bikepower.  It will 
calculate tables of data for speed vs power given mass, efficiency, and
many other factors. It is C source code which will compile on any computer.
I can provide a DOS version.  There is a lot of text at the beginning which
explains norms and where a lot of the numbers came from.  From that you can
get a good idea of what it takes to go up a hill and how much power you have
to crank out to go fast.  In my case I can sustain about 250W at my AT while
pro riders can put out 500W+.  
  If anyone is interested in V'O2 max data I have my own and another 2 peoples
(those guys in the Kin. dept seem to think that this stuff is confidential and
will not give me their data base :-(
The data is breath by breath monitering O2, CO2, power, pulse, breath rate and
is accurate to < 2%.  I do not have my blood flow data yet or my rebreath data
although it was consistant with the actual data.  I have done 3 upright V'O2
max tests (50W/min start then 15W/min increase), a suppine one and a suppine
one with lower body negative pressure.  I will be doing another one soon so
that I can compare myself to last year at this time.  If anyone has hard V'O2
data I would love to see it.  I am esp. interested in good caliber riders.
  - Eric