Beware of PowerCranks

"Tim McNamara" wrote in message
...
In article ,
"Phil Holman" piholmanc@yourservice wrote:

"Tim McNamara" wrote in message
...
In article , "Phil
Holman" piholmanc@yourservice wrote:

wrote in message
ups.com...
On Jun 3, 5:46 am, wrote:
On Sat, 2 Jun 2007 19:39:13 -0700, "Phil Holman"

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.

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

Well, the difference was in gross efficiency, not in power.
Frank Day calls them PowerCranks, not EfficiencyCranks. Phil may
know whether there has been a published RCT that shows an
increase in power.


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.

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

I'll assume you are talking about a theoretical ceiling and not the
difference in the same athlete being in shape and not in shape. The
theoretical ceiling is biologically determined but what biologically
constitutes that ceiling is still up for discussion.

As I understand it (it's been a while since I had any reason to look
into this stuff and maybe new data has come to light in the interim),
if
your VO max is 60 ml/kg/min then that is basically it. You can't
"train
up" your VO2 by 15.6% at least from the data I had looked at a few
years
back.

I'll resist the urge to challenge your understanding on the basis of a
rider who loses 5 kg of body weight. When dealing with PCs, we are not
interested in that aspect of any VO2Max improvement.


Miguel Indurain's published VO2 max was 88 ml/kg/min which is very
much
at the high end. Lemond's was reported to be over 90 ml/kg/min. A
training technique that would net guys think this a 15.6% increase
would
make them invincible. Nobody could touch them in an event like the
Tour
de France. You can't get even those kinds of gains by doping.

You're not going to see those kind of gains in athletes who have
maximized their training potential. In any event, VO2Max is a poor
predictor of race performance within a strata of racing abilities. From
the test, it is not clear whether actual 02 uptake was measured or if
VO2Max was estimated from the time to exhaustion in the incremental
test.


There are things you can train up by quite a bit, such as your
sustained
power output at lactate threshold, Wingate test, etc. Those things
are
important and can make a big difference in race results.

Yep. Ive alluded to the fact that an appropriate test needs to be done
with these things.
I.e. measure what is directly attributable to racing performance.


PowerCranks have always been marketed a bit too much like the
Second Coming for my tastes.

I thought you of all people could separate the science from the
emotion.

Hype annoys me, what can I say. When the hype seems mighty
unrealistic,
I get suspicious of there being a dose of snake oil in the mix. IMHO
people who are extremely competitive have a tendency to be a bit
gullible when it comes to things that promise improved performance.

Of interest to me would be whether whatever benefits are gained from
PowerCranks are durable. When people go back to regular cranks for
racing, do the maintain the neuromuscular pattern that a PowerCrank is
supposed to develop? Or do they go back to normal riding quickly? Do
they have to "brush up" with the PowerCranks periodically? My hunch
is
that the muscle recruitment pattern is quickly unlearned and the rider
goes back to a normal pedal stroke within a week or so after returning
to using normal cranks.

From my experience, it's subject to the same reversible process as
regular training. How much fitness do you think you'll lose in a week? I
haven't pedaled a PC in about 3 years but I can still employ the
technique for sustained periods because I still maintain the riding
technique with regular cranks.

Phil H

In article ,
"Phil Holman" piholmanc@yourservice wrote:

"Tim McNamara" wrote in message
...
In article , "Phil
Holman" piholmanc@yourservice wrote:

"Tim McNamara" wrote in message
...
In article , "Phil
Holman" piholmanc@yourservice wrote:

wrote in message
ups.com...
On Jun 3, 5:46 am, wrote:
On Sat, 2 Jun 2007 19:39:13 -0700, "Phil Holman"

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.

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

Well, the difference was in gross efficiency, not in power.
Frank Day calls them PowerCranks, not EfficiencyCranks. Phil
may know whether there has been a published RCT that shows an
increase in power.


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.

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

I'll assume you are talking about a theoretical ceiling and not
the difference in the same athlete being in shape and not in
shape. The theoretical ceiling is biologically determined but what
biologically constitutes that ceiling is still up for discussion.

As I understand it (it's been a while since I had any reason to
look into this stuff and maybe new data has come to light in the
interim), if your VO max is 60 ml/kg/min then that is basically it.
You can't "train up" your VO2 by 15.6% at least from the data I
had looked at a few years back.

I'll resist the urge to challenge your understanding on the basis of
a rider who loses 5 kg of body weight. When dealing with PCs, we are
not interested in that aspect of any VO2Max improvement.

That's good, because of course PowerCranks would have no different
effect on this than any other cranks. That's simply a matter of weight
loss.

Miguel Indurain's published VO2 max was 88 ml/kg/min which is very
much at the high end. Lemond's was reported to be over 90
ml/kg/min. A training technique that would net guys think this a
15.6% increase would make them invincible. Nobody could touch them
in an event like the Tour de France. You can't get even those
kinds of gains by doping.

You're not going to see those kind of gains in athletes who have
maximized their training potential. In any event, VO2Max is a poor
predictor of race performance within a strata of racing abilities.
From the test, it is not clear whether actual 02 uptake was measured
or if VO2Max was estimated from the time to exhaustion in the
incremental test.

VO2 is not the sole determinant of athletic performance- if it was, all
we'd have to do is measure VO2 max and we'd know the winner. However,
given that the literature used to indicate that VO2 was basically
genetically determined- whether that is still the case I don't know- it
seems highly unlikely that one can train up one's VO2 by 15.6%.

There are things you can train up by quite a bit, such as your
sustained power output at lactate threshold, Wingate test, etc.
Those things are important and can make a big difference in race
results.

Yep. Ive alluded to the fact that an appropriate test needs to be
done with these things. I.e. measure what is directly attributable to
racing performance.


PowerCranks have always been marketed a bit too much like the
Second Coming for my tastes.

I thought you of all people could separate the science from the
emotion.

Hype annoys me, what can I say. When the hype seems mighty
unrealistic, I get suspicious of there being a dose of snake oil in
the mix. IMHO people who are extremely competitive have a tendency
to be a bit gullible when it comes to things that promise improved
performance.

Of interest to me would be whether whatever benefits are gained
from PowerCranks are durable. When people go back to regular
cranks for racing, do the maintain the neuromuscular pattern that a
PowerCrank is supposed to develop? Or do they go back to normal
riding quickly? Do they have to "brush up" with the PowerCranks
periodically? My hunch is that the muscle recruitment pattern is
quickly unlearned and the rider goes back to a normal pedal stroke
within a week or so after returning to using normal cranks.

From my experience, it's subject to the same reversible process as
regular training. How much fitness do you think you'll lose in a
week? I haven't pedaled a PC in about 3 years but I can still employ
the technique for sustained periods because I still maintain the
riding technique with regular cranks.

The purported unique benefit of PowerCranks is as much neurological as
muscular. The rider has to develop a different pattern of muscle
recruitment and develop new "muscle memory." That pattern of muscle
recruitment is not necessary on regular cranks, and I suspect that the
new pattern would be lost quickly- perhaps in a couple of rides.

On Sun, 03 Jun 2007 19:26:41 -0500, Tim McNamara
wrote:

However,
given that the literature used to indicate that VO2 was basically
genetically determined- whether that is still the case I don't know- it
seems highly unlikely that one can train up one's VO2 by 15.6%.

An untrained person can, with training, increase VO2max that much.
But once someone has been training seriously for some time they can't.
--
JT
****************************
Remove "remove" to reply
Visit http://www.jt10000.com
****************************

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?
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

"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.

Phil H

"Tim McNamara" wrote in message
...
In article ,
"Phil Holman" piholmanc@yourservice wrote:

"Tim McNamara" wrote in message
...
In article , "Phil
Holman" piholmanc@yourservice wrote:

"Tim McNamara" wrote in message
...
In article , "Phil
Holman" piholmanc@yourservice wrote:

wrote in message
ups.com...
On Jun 3, 5:46 am, wrote:
On Sat, 2 Jun 2007 19:39:13 -0700, "Phil Holman"

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.

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

Well, the difference was in gross efficiency, not in power.
Frank Day calls them PowerCranks, not EfficiencyCranks. Phil
may know whether there has been a published RCT that shows an
increase in power.


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.

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

I'll assume you are talking about a theoretical ceiling and not
the difference in the same athlete being in shape and not in
shape. The theoretical ceiling is biologically determined but what
biologically constitutes that ceiling is still up for discussion.

As I understand it (it's been a while since I had any reason to
look into this stuff and maybe new data has come to light in the
interim), if your VO max is 60 ml/kg/min then that is basically it.
You can't "train up" your VO2 by 15.6% at least from the data I
had looked at a few years back.

I'll resist the urge to challenge your understanding on the basis of
a rider who loses 5 kg of body weight. When dealing with PCs, we are
not interested in that aspect of any VO2Max improvement.

That's good, because of course PowerCranks would have no different
effect on this than any other cranks. That's simply a matter of
weight
loss.

There is the argument that any improvement means the previous value
wasn't the true max.


Miguel Indurain's published VO2 max was 88 ml/kg/min which is very
much at the high end. Lemond's was reported to be over 90
ml/kg/min. A training technique that would net guys think this a
15.6% increase would make them invincible. Nobody could touch them
in an event like the Tour de France. You can't get even those
kinds of gains by doping.

You're not going to see those kind of gains in athletes who have
maximized their training potential. In any event, VO2Max is a poor
predictor of race performance within a strata of racing abilities.
From the test, it is not clear whether actual 02 uptake was measured
or if VO2Max was estimated from the time to exhaustion in the
incremental test.

VO2 is not the sole determinant of athletic performance- if it was,
all
we'd have to do is measure VO2 max and we'd know the winner. However,
given that the literature used to indicate that VO2 was basically
genetically determined- whether that is still the case I don't know-
it
seems highly unlikely that one can train up one's VO2 by 15.6%.

http://www.ncbi.nlm.nih.gov/sites/en...RVAbstractPlus

I think you've interpretted theoretical ceiling improvement to mean the
normal kinds of improvements seen by athletes who employ new training
techniques etc.
Once again the "any improvement means the previous value wasn't the true
max" argument applies.

There are things you can train up by quite a bit, such as your
sustained power output at lactate threshold, Wingate test, etc.
Those things are important and can make a big difference in race
results.

Yep. Ive alluded to the fact that an appropriate test needs to be
done with these things. I.e. measure what is directly attributable to
racing performance.


PowerCranks have always been marketed a bit too much like the
Second Coming for my tastes.

I thought you of all people could separate the science from the
emotion.

Hype annoys me, what can I say. When the hype seems mighty
unrealistic, I get suspicious of there being a dose of snake oil in
the mix. IMHO people who are extremely competitive have a tendency
to be a bit gullible when it comes to things that promise improved
performance.

Of interest to me would be whether whatever benefits are gained
from PowerCranks are durable. When people go back to regular
cranks for racing, do the maintain the neuromuscular pattern that a
PowerCrank is supposed to develop? Or do they go back to normal
riding quickly? Do they have to "brush up" with the PowerCranks
periodically? My hunch is that the muscle recruitment pattern is
quickly unlearned and the rider goes back to a normal pedal stroke
within a week or so after returning to using normal cranks.

From my experience, it's subject to the same reversible process as
regular training. How much fitness do you think you'll lose in a
week? I haven't pedaled a PC in about 3 years but I can still employ
the technique for sustained periods because I still maintain the
riding technique with regular cranks.

The purported unique benefit of PowerCranks is as much neurological as
muscular. The rider has to develop a different pattern of muscle
recruitment and develop new "muscle memory." That pattern of muscle
recruitment is not necessary on regular cranks, and I suspect that the
new pattern would be lost quickly- perhaps in a couple of rides.

Now why would you think that? I can't think of one skill I've learned
that has significantly diminished and especially not in a week. Do you
suspect a loss in the ability to play the guitar in a week? This part of
the debate is much like arguing tire RR with those that haven't read the
article. I'm sure you can relate.

Phil H

In article ,
John Forrest Tomlinson wrote:

On Sun, 03 Jun 2007 19:26:41 -0500, Tim McNamara
wrote:

However, given that the literature used to indicate that VO2 was
basically genetically determined- whether that is still the case I
don't know- it seems highly unlikely that one can train up one's VO2
by 15.6%.

An untrained person can, with training, increase VO2max that much.

My understanding- which may be incorrect, I got this from an exercise
physiologist that tested our team back in 1996 and maybe understanding
has changed- is that you can't. You can change many other aspects of
fitness with training, but you can't increase VO2 max per kg of lean
muscle mass. You can increase your total VO2 by increasing your lean
muscle mass, but not your ml/kg/min rate- which is the measurement that
counts in endurance sports.

Now, again, there may be newer information that contradicts this and I
wouldn't know about it. I don't peruse the exercise physiology
literature, especially since I stopped racing at the end of 2000...

But once someone has been training seriously for some time they
can't.

And that is likely to be the target market for this product.

In article ,
"Phil Holman" piholmanc@yourservice wrote:

"Tim McNamara" wrote in message
...
In article , "Phil
Holman" piholmanc@yourservice wrote:

"Tim McNamara" wrote in message
...
In article , "Phil
Holman" piholmanc@yourservice wrote:

"Tim McNamara" wrote in message
...

snip

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

I'll assume you are talking about a theoretical ceiling and not
the difference in the same athlete being in shape and not in
shape. The theoretical ceiling is biologically determined but
what biologically constitutes that ceiling is still up for
discussion.

As I understand it (it's been a while since I had any reason to
look into this stuff and maybe new data has come to light in the
interim), if your VO max is 60 ml/kg/min then that is basically
it.
You can't "train up" your VO2 by 15.6% at least from the data I
had looked at a few years back.

I'll resist the urge to challenge your understanding on the basis
of a rider who loses 5 kg of body weight. When dealing with PCs,
we are not interested in that aspect of any VO2Max improvement.

That's good, because of course PowerCranks would have no different
effect on this than any other cranks. That's simply a matter of
weight loss.

There is the argument that any improvement means the previous value
wasn't the true max.

Hmmm, I suppose but then we assume uncontrollable variables that make
the comparative measurements useless.

snip

VO2 is not the sole determinant of athletic performance- if it was,
all we'd have to do is measure VO2 max and we'd know the winner.
However, given that the literature used to indicate that VO2 was
basically genetically determined- whether that is still the case I
don't know- it seems highly unlikely that one can train up one's
VO2 by 15.6%.

http://www.ncbi.nlm.nih.gov/sites/en...howDetailView&
TermToSe
arch=16876479&itool=EntrezSystem2.PEntrez.Pubmed.P ubmed_ResultsPanel.P
ubmed_RV AbstractPlus

I think you've interpretted theoretical ceiling improvement to mean
the normal kinds of improvements seen by athletes who employ new
training techniques etc. Once again the "any improvement means the
previous value wasn't the true max" argument applies.

Thanks for the cite. There were too many jargonicious terms in that
abstract for me to sort out at 11:24 PM on a Sunday night. They're
probably transparent to a physiatrist or exercise physiologist.

snip

Of interest to me would be whether whatever benefits are gained
from PowerCranks are durable. When people go back to regular
cranks for racing, do the maintain the neuromuscular pattern
that a PowerCrank is supposed to develop? Or do they go back to
normal riding quickly? Do they have to "brush up" with the
PowerCranks periodically? My hunch is that the muscle
recruitment pattern is quickly unlearned and the rider goes back
to a normal pedal stroke within a week or so after returning to
using normal cranks.

From my experience, it's subject to the same reversible process as
regular training. How much fitness do you think you'll lose in a
week? I haven't pedaled a PC in about 3 years but I can still
employ the technique for sustained periods because I still
maintain the riding technique with regular cranks.

The purported unique benefit of PowerCranks is as much neurological
as muscular. The rider has to develop a different pattern of
muscle recruitment and develop new "muscle memory." That pattern
of muscle recruitment is not necessary on regular cranks, and I
suspect that the new pattern would be lost quickly- perhaps in a
couple of rides.

Now why would you think that? I can't think of one skill I've learned
that has significantly diminished and especially not in a week. Do
you suspect a loss in the ability to play the guitar in a week?

My comment on this comes out my background in psychology. I don't have
a formal background in the sub-field of kinesiology- which would be
relevant to the discussion- so it's quite possible I've got it wrong.
The nervous system learns muscle recruitment patterns through repetition
and indeed part of the training of any sport with repetitive movements
is to refine that recruitment pattern. The pattern is maintained with
repetition and decays with disuse. If you've had enough repetition,
then you'll pick it back up quickly.

I play guitar and the difference in my chops is noticeable to me if I
don't play for a day. If I don't play for a couple days, it's painfully
noticeable. If I didn't play for three days, you'd notice. If I don't
play guitar for a week, which happens sometimes during the summer when I
go out for a bike ride right after work and don't come home until dark,
it takes me an hour or more of running scales and going through chord
progressions to regain my customary level of fluency, for example. And
I don't have to play a lot- a half hour a day or so- to maintain the
motor skills (the creative skills are another matter :-P ).

In the case of PowerCranks, my thinking is this: the average racer who
buys these will already have had years of training on regular cranks
with millions of repetitions of the pedaling motion. Average Racer buys
the PCs, puts them on his bike and diligently follows the training
protocol. He learns to lift his legs up and over the top of the
rotation and into the power stroke. He rides with the cranks enough to
develop the new muscular recruitment pattern and doesn't have to
consciously think "up and over" with each pedal stroke. Thus he gains
the signal benefit of PCs, which is that the leg pushing down through
the power stroke isn't being resisted by the weight of the rising leg
coming up through the rest stroke.

Well and good. But in races and on group rides, he might switch to a
bike with regular cranks due to various reasons. Now he doesn't have to
lift that rising leg any more, and the long-established "normal" pattern
of muscle recruitment would probably tend to rapidly reestablish itself-
just like guitarists lapsing back into a familiar pentatonic scale in a
performance setting rather than playing the Mixolydian scale that
they've been learning to use in rehearsal. The question to me is "how
durable is the new pattern of muscle recruitment" when the rider returns
to normal cranks. An hour? A day? A week? A month? Once the pattern
is established, does the rider have to use the PCs daily to maintain
those cited gains in efficiency?

I could readily imagine the rider falling back into a normal pedaling
muscle recruitment pattern within 30 minutes. But I could also be
entirely wrong on that, or there may be quite a bit of variety on a
case-by-case basis.

Interestingly PCs are the reverse of riding a fixed gear. The old
belief is that fixed gear bikes are good for your spin. My experience,
and that of most of the folks I have asked that do fixed gear winter
training, is that when you get back on the freewheel bike you're
pedaling squares and your spin is worse. The fixed gear's ability to
raise the rider's leg with the momentum of the bike- which is part of
what makes a fixed gear feel easier to ride than a freewheel gear of the
same development- changes the muscle recruitment pattern fairly quickly.
I've noticed it after a single midsummer fixed gear ride.

So, in a roundabout way, that's why I would think that. Sorry for the
excess verbosity and rather nonlinear approach to answering your
question.

This part of the debate is much like arguing tire RR with those that
haven't read the article. I'm sure you can relate.

I'm sorry to be a drag on the discussion.

On Jun 4, 4:07 am, "Phil Holman" piholmanc@yourservice wrote:
There is the argument that any improvement means the previous value
wasn't the true max.

and

Once again the "any improvement means the previous value wasn't the true
max" argument applies.

Wouldn't that argument mean that if you did observe a change in VO2Max
(in ml/kg/min) then the previous value was faulty and shouldn't be
used as a basis for comparison? If one subscribed to that argument,
both the improvement and VO2Max and the improvement in power should be
discounted.

"Tim McNamara" wrote in message
VO2 is not the sole determinant of athletic performance- if it was,
all we'd have to do is measure VO2 max and we'd know the winner.

Well, it's true that VO2 isn't the sole determinant of athletic
performance, but it's a better determinant than VO2Max:
http://anonymous.coward.free.fr/rbr/coyle.png

On Jun 4, 6:20 am, Tim McNamara wrote:
You can change many other aspects of
fitness with training, but you can't increase VO2 max per kg of lean
muscle mass. You can increase your total VO2 by increasing your lean
muscle mass, but not your ml/kg/min rate- which is the measurement that
counts in endurance sports.

You've answered your own question. Mass-standardized VO2Max is
typically measured in terms of ml/kg/min, not ml/lean kg/min.