Tune Power Tap vs. Velodyne
Sam
that I am not impressed with your effort.
Lisa <andya...@erols.com> wrote:
>Despite what your newsreader might say, I and not my wife am 100%
>responsible for the following gibberish...
>
>Andrew Coggan
>
>> I just finished a workout on my Velodyne in constant workload
>> (ergometer) mode,
>> riding for 4-5 min at various power outputs (okay, I'll admit it - at
>> the highest power
>> output I couldn't go that long, and therefore settled for two shorter
>> "stints", which I
>> averaged). After giving myself and the Velodyne 30 s or so to settle in
>> at each power
>> output, I collected data using the Tune Power Tap's interval mode. And
>> what I found
>> was (drum roll please)......
>>
>> Velodyne power (W) 50,100,150,200,250,300,350,400
>>
>> Tune Power Tap (W) 51,101,150,197,245,292,344,396
>>
>> I've subjected the data to regression analysis, done residual and
>> Bland-Altman plots,
>> etc., but rather than bore you all with statistics, let me just say that
>> the bottom line is that the power values are not significantly
>> different. Since I have previously validated my Velodyne (first using
>> measurements of oxygen uptake and later using an SRM
>> crank* that itself had been validated against a mechanically-braked
>> Monark ergometer
>> - see http://www.collinear.com for details), I would conclude that, at
>> least when
>> making measurements over longer intervals, the Power Tap lives up to its
>> claim of +/-
>> 1.5% accuracy (although individual data points differ by as much as
>> 2.7%, on average
>> the difference is 0.7%).
>>
>> *While the SRM and Velodyne data did not differ significantly, there was
>> a tendency
>> for the SRM power measurements to be ~2% higher. This makes sense when
>> you
>> consider power losses in the drive train, which are measured by the SRM
>> but not by
>> the Velodyne. As the data show above, the Power Tap tended to be
>> slightly but not
>> significantly lower than the Velodyne - thus, if and/or when somebody
>> compares an
>> SRM and a Power Tap, I wouldn't be surprised if there is a slight (<5%)
>> but
>> consistent difference between the two.
>>
>> One last note: in an additional attempt to test the accuracy of the
>> Power Tap, I put it
>> into torque mode, locked up the rear wheel, and hung a 1 kg
>> NBS-certified calibration
>> weight from the pedal spindle. Based on the crank arm length, gear
>> ratio, etc., it is
>> possible calculate the expected torque at the rear hub. Unfortunately,
>> while the
>> measured and expected values agreed (8 in-lbs), the precision of this
>> approach is too
>> low to be of any real value, because the Power Tap only reports torque
>> to the nearest
>> whole number. I therefore need a bigger (but certified) weight, or a
>> longer lever arm.
Sam
abstract form?
"Jonathan Cane" <jon...@erols.com> wrote:
>Jay Guthrie <Jgut...@isd.net> wrote in message
>news:92716976...@news.remarQ.com...
>> How about testing my Computrainer for me sometime? I wonder how that
>would
>> do?
>
>I studied a CompuTrainer (in ergometer mode) against an Lode ergometer a few
>years back and found no significant differences at wattages from 50-300.
>Here's the abstract:
>
>A COMPARISON OF THE COMPUTRAINER LOAD SIMULATOR AND TRADITIONAL ERGOMETRY
>
>J. Cane, B. Seidman, J. Sowash, R.M. Otto. FACSM.&J. Wygand Human
>Performance Lab, Adelphi University, Garden City, NY
>
>To compare the metabolic response of a CompuTrainer RacerMate 800 (CT)(a
>computer aided load simulator) to a Lodi ergometer (LO)(A traditional
>validated workload ergometer), eleven male cyclists (Cat 2-4/triathletes)
>performed randomly assigned GXT trials on both CT and LO. CT allows a
>subject to use his own cycle which may result in a more accurate application
>to the competitive environment. Trials were performed 6 to 14 days apart and
>consisted of five three minute work stages of 100, 150, 200, 250, and 300W
>at a cadence of 85 rpm. Continuous open circuit spirometry was employed and
>heart rate was obtained by telemetry. The following data were obtained:
>
>Oxygen Consumption 1/min Heart Rate b/min
>
>watts 100 150 200 250 300 100 150 200 250 300
>CT 1.7 2.1 2.6 3.1 3.7 117 126 139 154 167
>LO 1.6 2.1 2.6 3.1 3.5 111 124 138 153 167
>
>Statistical analysis by ANOVA (P>.05) revealed no significant difference
>between modes in relation to V02, VE, RER, RPE, & HR.
>
>
>--
>==========================================================
>"Anywhere is walking distance if you have the time." (Steven Wright)
>
>
>>
>> Jay
>>
>>
>>
>> Andrew Albright wrote in message <7hvqf1$duo$1...@netnews.upenn.edu>...
>> >: Velodyne power (W) 50,100,150,200,250,300,350,400
Lisa
(ergometer) mode,
riding for 4-5 min at various power outputs (okay, I'll admit it - at
the highest power
output I couldn't go that long, and therefore settled for two shorter
"stints", which I
averaged). After giving myself and the Velodyne 30 s or so to settle in
at each power
output, I collected data using the Tune Power Tap's interval mode. And
what I found
was (drum roll please)......
Velodyne power (W) 50,100,150,200,250,300,350,400
Tune Power Tap (W) 51,101,150,197,245,292,344,396
I've subjected the data to regression analysis, done residual and
Lisa
responsible for the following gibberish...
Andrew Coggan
> I just finished a workout on my Velodyne in constant workload
Jay Guthrie
do?
Jay
Andrew Albright wrote in message <7hvqf1$duo$1...@netnews.upenn.edu>...
>: Velodyne power (W) 50,100,150,200,250,300,350,400
Andrew Albright
: Tune Power Tap (W) 51,101,150,197,245,292,344,396
So what is your overall conclusion for training with these thingamajigees?
How much does each one cost? Which one do you recommend buying?
And if I train with one, will I be better equiped, physically for long,
solo breakaways? I suck at time trails, but one day I would like to be
half-way decent. I think this kind of stuff is just what I need.
Thanks,
Andrew Albright
Jonathan Cane
would
> do?
I studied a CompuTrainer (in ergometer mode) against an Lode ergometer a few
years back and found no significant differences at wattages from 50-300.
Here's the abstract:
A COMPARISON OF THE COMPUTRAINER LOAD SIMULATOR AND TRADITIONAL ERGOMETRY
J. Cane, B. Seidman, J. Sowash, R.M. Otto. FACSM.&J. Wygand Human
Performance Lab, Adelphi University, Garden City, NY
To compare the metabolic response of a CompuTrainer RacerMate 800 (CT)(a
computer aided load simulator) to a Lodi ergometer (LO)(A traditional
validated workload ergometer), eleven male cyclists (Cat 2-4/triathletes)
performed randomly assigned GXT trials on both CT and LO. CT allows a
subject to use his own cycle which may result in a more accurate application
to the competitive environment. Trials were performed 6 to 14 days apart and
consisted of five three minute work stages of 100, 150, 200, 250, and 300W
at a cadence of 85 rpm. Continuous open circuit spirometry was employed and
heart rate was obtained by telemetry. The following data were obtained:
Oxygen Consumption 1/min Heart Rate b/min
watts 100 150 200 250 300 100 150 200 250 300
CT 1.7 2.1 2.6 3.1 3.7 117 126 139 154 167
LO 1.6 2.1 2.6 3.1 3.5 111 124 138 153 167
Statistical analysis by ANOVA (P>.05) revealed no significant difference
between modes in relation to V02, VE, RER, RPE, & HR.
--
==========================================================
"Anywhere is walking distance if you have the time." (Steven Wright)
>
> Jay
>
>
>
> Andrew Albright wrote in message <7hvqf1$duo$1...@netnews.upenn.edu>...
Andrew Coggan
tandem.
Andy
Sam wrote:
>
> Wow, doc, I was really impressed with your wife's effort--not
> that I am not impressed with your effort.
>
> Lisa <andya...@erols.com> wrote:
>
> >Despite what your newsreader might say, I and not my wife am 100%
> >responsible for the following gibberish...
> >
> >Andrew Coggan
(snip)
Andrew Coggan
First, thanks for sharing...
The "ergometer mode" qualification may be important, as one user I know
reports he always gets higher powers in race simulation mode. Rumor has
it that there is also a difference between the basic and pro models -
which one was it that you used?
Andrew Coggan
Jonathan Cane wrote:
> I studied a CompuTrainer (in ergometer mode) against an Lode ergometer a few
> years back and found no significant differences at wattages from 50-300.
> Here's the abstract:
(rest snipped in the interest of brevity - you can find the data on the
CT website if you haven't seen it before.)
cog...@my-dejanews.com
> : Velodyne power (W) 50,100,150,200,250,300,350,400
>
> : Tune Power Tap (W) 51,101,150,197,245,292,344,396
>
> So what is your overall conclusion for training with these
thingamajigees?
> How much does each one cost? Which one do you recommend buying?
I've had a Velodyne for almost 10 years, and find it extremely useful -
in fact, almost indispensible - for my training. Doing workouts on a
trainer isn't nearly as much fun as going for a ride with my wife or
with friends, but it is very effective and time efficient. When training
seriously, I typically use it in ergometer mode, in which case the
control over the power is key - I design a workout, and then I simply do
it - period, no ifs, ands, or buts, no guesswork, no fooling yourself
into thinking that you're overloading the system - it is all black and
white. To give an example: I'm currently doing 6 x 5 min intervals, and
in the last 6 weeks (since the Hump Race) have been able to raise the
power by 20%, w/o any increase in HR (are you listening, all you D20 40+
racers? <grin>). I therefore know for a fact that I am improving, and
also know that I will have to continue to raise the power if I want to
continue to improve.
10 years ago, the Velodyne sold for ~$1800...they have been out of
production for quite some time, but refurbished units are available, and
plans are to bring them back. See http://www.collinear.com for details.
The Tune Power Tap has the distinct advantage that I can now measure my
power "in the real world", not just when sweating away in my bike room.
Now that I've validated it, I have high hopes for how it will also help
w/ my training and racing, but I obvioulsy haven't used it enough (or
the SRM I borrowed for a few months a while back) to know for sure. In
general, I think that such devices will be more evolutionary than
revolutionary in terms of their impact on how people train, but there
will be some people they will have a more dramatic impact on. One
distinction that I think is worth mentioning is while the Power Tap
allows you to *measure* your power, it doesn't *control* it (like the
Velodyne or an ergometer can). It is therefore still up to you to supply
the motivation and "do your homework". To me, using an ergometer to
control power during training shifts the motivational burden a bit. I
therefore like having both the Velodyne and the Power Tap - the Power
Tap + a regular trainer doesn't quite equal a good,
electronically-controlled ergometer...it is more like having one of the
older mechanically-controlled ones, which almost every exercise
physiology lab in the world has moved beyond.
Info on the Power Tap can be found at http://www.etune.com. The system
retails for $769, with a pre-built wheel being ~$100 more.
> And if I train with one, will I be better equiped, physically for
long,
> solo breakaways? I suck at time trails, but one day I would like to
be
> half-way decent. I think this kind of stuff is just what I need.
To be really good at TTs and/or solo breakaways requires having the
genetic ability and training really, really hard - these devices can
help with the latter, but only so much.
BTW, from personal experience I can tell you one key for succeeding w/ a
solo break, and that is make sure that you don't take off before the end
of the neutral zone...otherwise the officials will make you return to
the field, but only after you've toasted yourself off the front for
30-35 miles. ;-)
--
Andrew Coggan
--== Sent via Deja.com http://www.deja.com/ ==--
---Share what you know. Learn what you don't.---
Ben Reuter
>How about testing my Computrainer for me sometime? I wonder how that would
I pilot tested an SRM vs a Computrainer when our Velodyne "died" last
fall and I needed to collect my dissertation data. Basically I found that
with a slick tire, cleaned with alcohol before each use and a "press-on
force" of 1 3/4 turns there were no significant differences up to ~380 W,.
At workloads higher than that I got a lot of slippage of the tire, which
reduced the W reading of the SRM.
Ben Reuter
Jonathan Cane
Sam <marat...@mindspring.com> wrote in message
news:3740ee17....@news.mindspring.com...
> Jonathan, did this get published anywhere other than in
>abstract form?
The abstract was published in Medicine and Science and Sports and Exercise
and presented at the ACSM Annual Conference. We had talked to Cycling
Science briefly about publication, but to the best of my knowledge, their
journal hasn't been published regularly for a while. Oh well. If anyone's
interested in the full paper and the methods used, I'd be happy to E-mail
it.
JC
==========================================================
"Anywhere is walking distance if you have the time." (Steven Wright)
>
>
> "Jonathan Cane" <jon...@erols.com> wrote:
>
> >Jay Guthrie <Jgut...@isd.net> wrote in message
> >news:92716976...@news.remarQ.com...
> >> How about testing my Computrainer for me sometime? I wonder how that
> >would
> >> do?
> >
> >I studied a CompuTrainer (in ergometer mode) against an Lode ergometer a
few
> >years back and found no significant differences at wattages from 50-300.
> >Here's the abstract:
> >
cog...@grecc.ab.umd.edu
Both your data and that in the abstract Jonathan (co-?) authored
indicate that the CT is accurate, at least in ergometer mode (I assume
from the description of your test that that is the mode you used).
However, I constantly hear from people who are sustaining unbelievable
power outputs on their CTs, and I have an e-pal who has extensively
compared his basic and pro models in ergometer and race simulation mode,
finding that both give lower values in the ergometer mode (with the pro
model giving values 5-10% lower than the basic model). I've therefore
been leaning towards the conclusion that the CT overestimates only in
race simulation mode (which is how most people use it, since it is more
interesting). My question to you is, did you have a chance to
somehow compare the two modes, either w/ or w/o the SRM?
Andy
"Ben Reuter" <reu...@mail.auburn.edu> wrote:
> Jay Guthrie wrote in message <92716976...@news.remarQ.com>...
> >How about testing my Computrainer for me sometime? I wonder how that
would
>
> I pilot tested an SRM vs a Computrainer when our Velodyne "died"
last
> fall and I needed to collect my dissertation data. Basically I found
that
> with a slick tire, cleaned with alcohol before each use and a
"press-on
> force" of 1 3/4 turns there were no significant differences up to ~380
W,.
> At workloads higher than that I got a lot of slippage of the tire,
which
> reduced the W reading of the SRM.
Rick Denney
wrote:
[snipped report showing Power Tap is accurate]
Must... resist.... must... fight... the... urge...
Eeeeeh.... ooooohhhh.... noooooo...
[hand reaches for wallet, stops, and is pulled back with great effort]
Rick "It would be easier if the damn thing were as expensive as an
SRM" Denney
Ben Reuter
cog...@grecc.ab.umd.edu wrote in message <7i1700$cv$1...@nnrp1.deja.com>...
>). My question to you is, did you have a chance to
>somehow compare the two modes, either w/ or w/o the SRM?
I didn't get a chance to compare the Computrainer in the ergo and race
simulation modes vs the SRM, but it is interesting that you mention the over
estimation of power in the race simulation mode. I corresponded with a
researcher in Canada who was doing work with mountain bikers using the
Computrainer. He mentioned that when they used a 26" slick tire (mountain
bike tire, not a tri bike tire to those triathletes out there) the power
values in the ergo mode were consistently higher than when they used a
similar protocol with a road bike (they were using it in conjunction with an
SRM I believe)
. I guess the take home message w a Computrainer is that it's a great
consumer device, that maybe a usefull research device in the proper hands,
with the proper protocol, etc.
Ben Reuter
Jonathan Cane
--
==========================================================
"Anywhere is walking distance if you have the time." (Steven Wright)
Andrew Coggan <andya...@erols.com> wrote in message
news:3743E6...@erols.com...
> Jonathan,
>
> First, thanks for sharing...
My pleasure.
>
> The "ergometer mode" qualification may be important, as one user I know
> reports he always gets higher powers in race simulation mode. Rumor has
> it that there is also a difference between the basic and pro models -
> which one was it that you used?
>
I used the basic model and would agree from personal experience that the
race mode seems to result in higher numbers. The ergometer mode seems to
work well, at least at the cadence I studied, but I would be reluctant to
draw any other conclusions. Again speaking strictly from personal
experience, the CT seems to be very consistant in both modes, which allows
me to duplicate and compare workouts.
One other interesting observation - I recently replaced the handlebar unit
and parts of the load generator. Either I got considerably stronger in the
month it was away, or there was some variation caused be one or more of the
new parts.
JC
>