[Phys-L] exercise physics and physiology

[John Denker <jsd@av8n.com>]

I changed the Subject: line because this has drifted pretty
far from the question about "energy resources" ... but it is
an interesting and important topic unto itself.

On 12/13/2014 10:41 AM, Dan Beeker wrote:
> It takes a lot of effort (I was going to say work : ) to run even a 
> 100 watt load for any reasonable length of time.

Note that the exercycle is probably pretty inefficient, so to
run a 100 watt light bulb the rider is probably putting out well
over 100 watts.

To put that in perspective:  I've seen reports of a Tour de France 
rider averaging 387 watts for an hour, and averaging 296 watts for
six hours.
  http://www.ironman.com/triathlon/news/articles/2014/07/tour-de-france-ironman-data-comparison.aspx

387 W is more than half a horsepower.  That seems like a lot.

A more systematic search would probably turn up higher numbers.

==============

Once upon a time I signed up for some aerobics lessons.  The 
first two sentences uttered by the instructor defined "aerobic"
and "anaerobic" ... and got them both diametrically wrong. 
She defined "aerobic" to mean that you're working hard enough
to be really huffing and puffing, whereas "anaerobic" is
when you are just sitting around.  When I suggested those
definitions were backwards relative to the obvious etymology,
and relative to how the word was used in the physics and
physiology literature, she pulled rank: "Who is the certified
aerobics instructor here, you or me????"

Things went downhill from there.  She launched into a
detailed harangue about metabolism, CO2, lactic acid,
et cetera, almost every word of which was wrong.

On a more positive note, here is an interesting article:
  Kravitz and Dalleck
  "Lactate Theshold Training"
  http://www.unm.edu/~lkravitz/Article%20folder/lactatethreshold.html

> > All world and Olympic endurance athletes incorporate lactate 
> > threshold training into their workouts.

> > Studies have repeatedly found high correlations between
> > performance in endurance events such as running, cycling, and
> > race-walking and the maximal steady-state workload at the lactate
> > threshold

> > there are many researchers who strongly object to the use of the
> > term anaerobic threshold, believing it is misleading.

Even if such a thing existed, there would be no known way
of measuring it, so it's not useful.  This stands in
contrast to the lactate threshold, which is measurable
and known to be useful ... even if the underlying mechanisms
are complicated and ill-understood.

The Kravitz and Dallek article is pithy but not hard to
read if you take your time.  I'm not an expert, but the
authors seem to know what they're talking about.  The
article has a dozen citations to the primary literature.

The article is pretty much a point-by-point refutation of
everything my "certified aerobics instructor" tried to 
tell me.  Among other things:  If somebody offers you a
program to "quickly" build up your strength and endurance,
don't take it.  You should plan on /gradually/ building up
your strength and endurance. 10% or 20% per week is plenty
fast enough.