Beware of PowerCranks

On Jun 2, 9:39 pm, "Phil Holman" piholmanc@yourservice wrote:

Frank Day. His last posts here were after a scientific study showed a
statistically significant 1.5% gross efficiency improvement. The experts
here still wouldn't buy it.

It wasn't a case of "not buying it", but how to interpret it.

Andy Coggan

On Jun 3, 12:58 pm, "Phil Holman" piholmanc@yourservice wrote:

I just checked their website and found another study of trained cyclists
that showed a 15.6% increase in VO2max and an 11.6% icrease in max
power.

Yeah, training will do that for you (or at least it should).

Andy Coggan (whose sustainable power is up 11% in the last 10 wk)

On Jun 3, 3:02 pm, "Phil Holman" piholmanc@yourservice wrote:

What does it take to get an appropriate and properly
designed test?

Somebody who knows what they're doing? ;-)

Andy Coggan

On Jun 3, 3:16 pm, Tim McNamara wrote:

My understanding- which may not be correct- is that VO2 max is
biologically determined and that training does not significantly change
this.

Your understanding is incorrect: VO2max (in mL/min/kg) increases by
15-25% with just moderate training, and by up to 60% with more
prolonged/extensive training. Even elite athletes who have been
training for many years routinely experience swings in VO2max of up to
10% (sometimes more) between the peak of in-season fitness and the
nadir of off-season slothdom.

Andy Coggan

On Jun 5, 11:04 pm, "Phil Holman" piholmanc@yourservice wrote:
wrote in message

In recent times, steam RR locomotives, although not rated in Horse
Power (but rather "tractive effort", the pull at which the wheels
would spin) had a conversion chart to HP based on grate area in the
fire box which governs how much heat can be transferred to steam in
the boiler. Grate area is closely similar to lung displacement for
physically fit racers. That is what limits climbing or TT ability,
not ankling, pedaling style or other external means.

You continue to repeat this misconception. Lung displacement or lung
capacity is not the limiting factor in climbing or TTing or cycling in
general. If you understood the cause and effect elements you would
understand that extreme "out of breath" is caused by excess CO2 in the
blood stream as a result of lactic buffering.

Great! Now we have one engineer feeding misconceptions about how
physiology functions to another engineer...

Fact: CO2 plays only a very limited role in regulating ventilation
during exercise.

That is, the limits of
aerobic capacity were reached upstream (cardiac output, blood muscle
interface limitations etc) and no further limitations are imposed by the
lungs. It wouldn't matter if you doubled lung capacity, blood lactate
concentrations wouldn't change and this is the culminating event in
limiting aerobic performance. Heavy breathing is an effect not a cause.

In fact, mild-to-moderate arterial desaturation tends to occur during
maximal exercise in a significant portion of the population (at least
discounting young, healthy, untrained men!), indicating that, at least
to some extent, aerobic capacity (i.e., VO2max) is limited, in part,
by pulmonary function.

Andy Coggan

Andy Coggan wrote:
On Jun 5, 11:04 pm, "Phil Holman" piholmanc@yourservice wrote:
wrote in message

In recent times, steam RR locomotives, although not rated in Horse
Power (but rather "tractive effort", the pull at which the wheels
would spin) had a conversion chart to HP based on grate area in the
fire box which governs how much heat can be transferred to steam in
the boiler. Grate area is closely similar to lung displacement for
physically fit racers. That is what limits climbing or TT ability,
not ankling, pedaling style or other external means.
You continue to repeat this misconception. Lung displacement or lung
capacity is not the limiting factor in climbing or TTing or cycling in
general. If you understood the cause and effect elements you would
understand that extreme "out of breath" is caused by excess CO2 in the
blood stream as a result of lactic buffering.

Great! Now we have one engineer feeding misconceptions about how
physiology functions to another engineer...

Fact: CO2 plays only a very limited role in regulating ventilation
during exercise.

Another fact: The reason you can't hold your breath for more than about
2 minutes, even while sitting, is the CO2 buildup in the airways causing
a forced breathing reflex.
Even someone who is not working out can exercise the lungs, as I used to
do during long car commutes. Inhale to the absolute maximum and hold for
as long as possible. I gained some lung volume from doing that on long
boring stretches of road. Sounds lame, but it worked.

That is, the limits of
aerobic capacity were reached upstream (cardiac output, blood muscle
interface limitations etc) and no further limitations are imposed by the
lungs. It wouldn't matter if you doubled lung capacity, blood lactate
concentrations wouldn't change and this is the culminating event in
limiting aerobic performance. Heavy breathing is an effect not a cause.

In fact, mild-to-moderate arterial desaturation tends to occur during
maximal exercise in a significant portion of the population (at least
discounting young, healthy, untrained men!), indicating that, at least
to some extent, aerobic capacity (i.e., VO2max) is limited, in part,
by pulmonary function.

Andy Coggan

I have to wonder whether it is my legs anaerobic capacity that is being
depleted in my daily 'suicide' runs, as in sprint until no longer able
to run at all. Only after dropping to a walk does my heart and lungs get
the idea they should be doing more. My breathing and pulse don't seem to
peak until about 30 seconds after the run of about the same time.
Is that a normal thing or am I just breaking the rules of exercise???
Cycling I can't even get to that state of totally out of breath and high
pulse rate. Maybe an imbalance between leg fitness and cardio fitness??
Bill Baka

In article . com,
Andy Coggan wrote:

On Jun 3, 3:16 pm, Tim McNamara wrote:

My understanding- which may not be correct- is that VO2 max is
biologically determined and that training does not significantly
change this.

Your understanding is incorrect: VO2max (in mL/min/kg) increases by
15-25% with just moderate training, and by up to 60% with more
prolonged/extensive training. Even elite athletes who have been
training for many years routinely experience swings in VO2max of up
to 10% (sometimes more) between the peak of in-season fitness and the
nadir of off-season slothdom.

Thanks. I wish I still was in touch with that exercise physiologist to
update him...

On Jun 3, 9:01 pm, "Phil Holman" piholmanc@yourservice wrote:
"A Muzi" wrote in message

...





Ride Faster wrote:
I had the same experience with PowerCranks. This product is
garbage.

" wrote:
It's really outrageous for them Powercrank to charge so much for a
faulty design.

"Tim McNamara" wrote
The proprietor of PowerCranks used to post here to rebut
criticisms, but
I haven't seen anything from him for a while. Basically I suspect
that
the price is high because (1) he promises that his product will
make you
faster for which competitive people will pay lots of money and (2)
his
business is small enough that he doesn't get much by way of
economies of
scale to bring his production costs down.

"Phil Holman" piholmanc@yourservice wrote:
Frank Day. His last posts here were after a scientific study showed
a statistically significant 1.5% gross efficiency improvement. The
experts here still wouldn't buy it.

wrote:
No offense, but that sounds like 200 watts rising to 203 watts.

Wouldn't that be 200W reduced to a mere 197 watts?

No, but I know what you are getting at. For the same 200 watt output,
VO2 consumption reduces by 100*1.5/E = approx 6% less. From this we
infer that for the same O2 consumption, the athlete can output 212
watts.

Can that be safely inferred?

Andy Coggan

On Jun 7, 2:26 pm, Bill wrote:

The reason you can't hold your breath for more than about
2 minutes, even while sitting, is the CO2 buildup in the airways causing
a forced breathing reflex.

And this relates to the *eucapnic* regulation of ventilation during
exercise how?

Andy Coggan

On Jun 7, 3:26 pm, Bill wrote:
Andy Coggan wrote:
On Jun 5, 11:04 pm, "Phil Holman" piholmanc@yourservice wrote:
wrote in message

In recent times, steam RR locomotives, although not rated in Horse
Power (but rather "tractive effort", the pull at which the wheels
would spin) had a conversion chart to HP based on grate area in the
fire box which governs how much heat can be transferred to steam in
the boiler. Grate area is closely similar to lung displacement for
physically fit racers. That is what limits climbing or TT ability,
not ankling, pedaling style or other external means.
You continue to repeat this misconception. Lung displacement or lung
capacity is not the limiting factor in climbing or TTing or cycling in
general. If you understood the cause and effect elements you would
understand that extreme "out of breath" is caused by excess CO2 in the
blood stream as a result of lactic buffering.

Great! Now we have one engineer feeding misconceptions about how
physiology functions to another engineer...

Fact: CO2 plays only a very limited role in regulating ventilation
during exercise.

Another fact: The reason you can't hold your breath for more than about
2 minutes, even while sitting, is the CO2 buildup in the airways causing
a forced breathing reflex.
Even someone who is not working out can exercise the lungs, as I used to
do during long car commutes. Inhale to the absolute maximum and hold for
as long as possible. I gained some lung volume from doing that on long
boring stretches of road. Sounds lame, but it worked.

Guess all those pearl divers were faking it since you have concluded
it's not possible. I think Andy might know a little more on the
subject and have a bit more credibility.
Bill C