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RichD  
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 More options Oct 2 2012, 4:14 pm
Newsgroups: misc.fitness.weights, rec.martial-arts, rec.running, rec.bicycles.misc, rec.sport.tennis
From: RichD <r_delaney2...@yahoo.com>
Date: Tue, 2 Oct 2012 13:14:11 -0700 (PDT)
Local: Tues, Oct 2 2012 4:14 pm
Subject: Re: "fitness vs. efficiency"
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On Sep 23, "Existential Angst" <fit...@optonline.net> wrote:

> From a previous thread:

> > these burns require 2 steps at a time.

> Why?
> One step at a time, obviously churns the legs more -
> better for exercise, though maybe not so great,
> competitively.  (the issue of fitness  vs. efficiency is
> never discussed)
> =============================================

> I sort of misconstrued this point in the earlier thread, and it is really
> very inneresting

> I can tell you definitively that stair-sprinting 2 steps at a
> time generates about double the watts of 1 step at a time --
> no way single-step climbing could close that gap by much.
> And these measurements (my back-staircase antics) are, imo,
> near-laboratory quality -- not bec I am any great
> experimentalist, but because the method itself is so ultra-elegant:
> mgh divided by time, plain and simple, which anyone here can do.
> However, this doubling of watts with step size is true for
> GENERATED power, ie, mechanical watts.  Iow, if I were
> somehow hooked up to an electric generator,  I would produce
> double the electric power by sprinting 2-steps vs. 1-step.

> BUT......  How much energy would I actually be BURNING??
> RichD used the expression "churns the legs more",
> where "churning" would represent a kind of "internal
> energy expenditure" of leg motion not measured in (ie, not
> contributing to) stair climbed mechanical watts. Ditto the arm
> pumping!   And, is pretty much un-measurable,

> So the answer is:  No one knows the true calorie burn of either,
> unless really expensive tests were conducted in direct
> calorimeters, and even then the results might be fuzzy.

Human body is 20-25% efficient; 200 calories at an
external load, means 800 - 1000 cal. internally.
Considering that nature and evolution is very efficient, this is
astonishingly bad.

> It *might* could be, that furious single-step climbing *burns
> more calories* than 2-step climbing, while *generating* much
> less power.  Intuitively/perceived exertion-wise I don't think this
> is so,

Seems clearly so to me.

You perform the same work, mgh, but churn the legs
twice as much.

> Which all reflects on the initial notion of "fitness vs. efficiency", which
> is a bit of a apples/oranges phrase.
> A better characterization of the issue would simply be "mechanical
> efficiency of physical exertion", which would directly reflect the stair
> climbing vs steps issue:   how much electricity could you generate
> from a given calorie burn vis a vis steps?

If you're a competitor (why isn't stair climbing a track
event?), you want to climb a given height, with maximum
thrust per calorie used.  It's a spint, not an endurance
event. Ditto for other anaerobic sports.

> From a pure fitness pov, all this is moot, bec really all we are
> intereested in is in fact the calorie burn itself.  Mechanical
> (generated) power is technically irrelevant here.

Right.  The goals and motivation of fitness are very different
than competition.

> But from a *competitive* pov, as alluded to up at the top, efficiency
> IS a very big deal.
> And there are at least two types, altho perhaps efficiency
> starts to blur with *technique/form*.
> One would be the sprinter, who wants the greatest fraction of
> his total thrust directed horizontally.
> Related is the marathoner, who also wants to maximize
> the horizontal component of his thrust, but who ALSO wants
> to maximize the energy efficiency of *the whole stride*, to
> *minimize* glycogen consumption.

> Could we generally assume that, in stair climbing, higher
> mechanical watts means higher cals/min?

True almost by definition.

> But less absolutely when comparing 1 step vs 2 steps.
> I personally think the calorie burn is higher, judging from perceived
> exertion, altho if the mechanical watts is doubled (from 2 step
> climbing), that may not mean the cal burn is doubled, so direct
> proportionality may not apply when the *gait* is shifted.
> I think the two calorie burns would be
> much closer than a factor of two, but still significantly different.

Efficiency will drop with more steps, assuming the same total
climb.  Leg churn -

But my point is, that's what you want!  Efficient form will
REDUCE calorie burn, which is counter-productive.
The point of non-competitive exercise is:
  weight control
  cardiovascular health
  genereral athleticism, e.g. balance, agility, quickness, etc.

If you hire a coach for running, or anything else, he'll
teach you the form the pros use, the most efficient.
He'll boast about his expertise there.  But for the
rec. runner, that isn't helpful!

This only applies to 'pure exercise'; running, biking,
swimming.  For skill activities, like tennis, players
want performance, so fitness, while important, isn't
the dominant consideration.

In some sports, the question is unclear.  I used to
do so-called martial arts, where technique and form
is emphasized.  Because it's presumably efficient,
hence more effective.  But the whole self defense story -
"defend yourself in the street" - is a crock, a sales
gimmick.  The most valuable benefit of karotty is
exercise.  So there, again, efficiency is not an
unmitigated gain.  But nobody ever acknowledges that.

There's been a vast growth in sport science and medicine
over the last 30 years, along with the recreational sport
industry.  But I've never seen anyone address this fitness
vs. (competitive) efficiency issue, which I say is crucial.

--
Rich


 
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