Real performance gains and modelling

[CoachFergie]

I saw this on Fixed Gear Fever and think it is an excellent (and not overly scientific) presentation (there are even some cool vids) on optimising performance in the individual pursuit.

http://www.dicklanevelodrome.com/node/1037

I have no association with the DLV and thank them for supplying this for free when I would happily pay for this type of information.

 

[Boeing]

nice link. ----------------

 

[Martin318is]

I have removed the unnecessary reference as it adds nothing to the thread. Enjoy

 

[CoachFergie]

Some more good s**t on aerodynamics and using a power meter to assess both this and performance.

Interbike presentation from Zipp, SRAM and Quarg.

 

[CoachFergie]

Here is a dumbing down of Jim Martin's presentation on crank length.

Dude your crank length's just fine.

 

[FrankDay]

I saw this on Fixed Gear Fever and think it is an excellent (and not overly scientific) presentation (there are even some cool vids) on optimising performance in the individual pursuit.

http://www.dicklanevelodrome.com/node/1037

I have no association with the DLV and thank them for supplying this for free when I would happily pay for this type of information.

That was a very interesting series of videos. The proof of any modeling program is the ability to predict outcome. I suspect that if they reverse engineered their program for their riders they could put in values that would be very predictive and help these riders optimize performance.

I did take issue with two things they said.

First, in the second video he said that pursuit would be faster on a straight track than on a velodrome. I don't believe that to be correct. I will state why after I mention my second issue.

Second, in the third video he doesn't seem to recognize that air speed is not equal to ground speed in the corners. This is because of the lean and the air speed of the major component of drag, the upper body and head, is substantially slower than the wheel speed. His model doesn't seem to account for this.

So, to me the fastest velodrome would be one with an 80º bank and a 4-6 foot radius and no straight. This way, the wheels would be moving at a speed of 30 mph but the head/shoulders would be moving at 5 mph. Air resistance would be minimized and speed would be maximized. As long as the rider could tolerate this condition this suggests that their calculation that speed should be faster on a straight track than a velodrome is flawed.

 

[CoachFergie]

It is being discussed on Fixed Gear Fever and some of their assumptions have been challenged. For example their suggestion that the surface resistance was high would have more to do with the joins in the concrete slabs than the actual smoothness (or lack of) of the track.

FGF Discussion on the DLV

 

[FrankDay]

It is being discussed on Fixed Gear Fever and some of their assumptions have been challenged. For example their suggestion that the surface resistance was high would have more to do with the joins in the concrete slabs than the actual smoothness (or lack of) of the track.

FGF Discussion on the DLV

Seems to me, from a modeling perspective, that is a silly argument. From the modeling perspective, rough is rough. Doesn't matter if it is rough due to surface roughness or discreet joints, it is simply trying to separate out the different issues mathematically. If the model predicts the behavior it is correct.

 

[veganrob]

Some more good s**t on aerodynamics and using a power meter to assess both this and performance.

Interbike presentation from Zipp, SRAM and Quarg.

Be a lot of Kool Aid at that presentation.

 

[CoachFergie]

Be a lot of Kool Aid at that presentation.

No doubt. But at least if you attend a sponsored session you know what you are in for.

I got an invite to a Nutrition Seminar for Young Athletes. I didn't attend because I am not young and would struggle to call myself an athlete. Turned out to be a big Usana pitch where all the ills of the world can be solved by 2 pills a day.

 

[Alex Simmons/RST]

Second, in the third video he doesn't seem to recognize that air speed is not equal to ground speed in the corners. This is because of the lean and the air speed of the major component of drag, the upper body and head, is substantially slower than the wheel speed. His model doesn't seem to account for this.

I can't specifically recall on this one, but some models do account for this, as well as additionally rolling resistance. When you really start looking at pursuit power meter data closely, you start to notice some very interesting things. Inspect a VE plot of the turn for instance and it shows some pretty interesting stuff, second order effects beyond the typically pseudo-sinusoidal pattern.

So, to me the fastest velodrome would be one with an 80º bank and a 4-6 foot radius and no straight. This way, the wheels would be moving at a speed of 30 mph but the head/shoulders would be moving at 5 mph. Air resistance would be minimized and speed would be maximized. As long as the rider could tolerate this condition this suggests that their calculation that speed should be faster on a straight track than a velodrome is flawed.

Which is counter to actual experience, i.e. the tracks (with similar conditions) with a larger turn radius are generally faster (e.g. Moscow, Sydney).

There are many factors at play, and a reduction in turn radius also increases rolling resistance as well.

 

[FrankDay]

Which is counter to actual experience, i.e. the tracks (with similar conditions) with a larger turn radius are generally faster (e.g. Moscow, Sydney).

Well, that may very well be true but their explanation to explain the phenomenon (assuming it to be true) doesn't make any sense to me.

There are many factors at play, and a reduction in turn radius also increases rolling resistance as well.

As I remember their model did account for the change in RR in the turns. Anyhow, I agree there are many factors at play here and I am simply pointing out that it seems the model is missing some important ones.

 

[CoachFergie]

Seems prudent that I post an example of how I use a power meter to measure gains in performance.

I will use the example of a rider I coach who has started using a power meter this year and has gone on to achieve great performances and great results.

It would be easy to claim that since he has started using a power meter that he has gone on to win two medals at Junior Worlds. But that would be confounded by the fact it's his first year in U19 and the first time he is eligible to compete in a Worlds level event. I could even show that he has achieved PB times for 200m, 1000m and 3000m but does this reflect an actual performance improvement?

I initially loaned him my powertap as I am testing a Power2Max meter and he used it in training as the powertap wheel was a training tyre and HP rim. Not suitable for racing and as the competition were on carbon wheels the the powertap put him at a disadvantage. But we did some testing and I established a baseline power based off that and the racing and efforts he did before he decided to use his carbon wheels where possible.

We set up a schedule of intervals based around power. This was in conjunction with the U19 NZ coach although we decided he need to do more extensive work than the intensive work the NZ coach recommended. I had followed the same plan with a Junior Worlds rider the year before with good results. From his intervals we saw a steady progression in power at the levels we were training at relative to the resistance and cadences he would need to ride at Moscow. Before he left for Junior Worlds we tested again and he added 80 watts to his test 2 months prior. I am realistic that a lot of this gain was learning effect but the benefit of the power meter was he could learn to pace his efforts and ensure that the cadence was similar to the one he would use in cadence.

A pitfall that many fall into is using a big gear or hills to generate more power than they could on an indoor track.

On his return and build up for 2012 Junior Worlds (rather continently in Invercargill) we have seen more power and know the training is on task. Because of this riders ability he rarely loses in NZ so tracking results would tell us very little about his actual performance gains. His times are improving but his coaching involves technical and tactical skills as well as physical gains. The power meter helps to measure his physical performance while it is more difficult to quantify technical or psychological gains.

He did set PBs in Moscow but that is a faster track than ILT in NZ and the weather was very warm by comparison to 2009 when the Junior Worlds were there yet winning times in some events (IP and Kilo) were slower but in others (TP and flying 200m) world records were set.

A huge gap between results and performances.

 

[CoachFergie]

In 2001 Asker Jeukendrup and Jim Martin wrote a very good review on where to spend money on improving cycling. For those not in academic circles here are a couple of interviews or articles on that paper outlining what they found...

http://www.cyclesportcoaching.com/Files/HowToSpendMoney.pdf

http://www.pezcyclingnews.com/default.asp?pg=fullstory&id=2946

 

[CoachFergie]

Just seen this.

http://www.jssm.org/vol10/n3/12/v10n3-12text.php

Would appear that even those in academic circles confuse measuring performance with enhancing performance.

It's another rehash of Swart et al 2009 study that found no difference between a group that looked at a number from a HR monitor and a Power meter.

The same result would have been found for both studies had they had one group watching Family Guy and another watching The Simpsons.

 

[CoachFergie]

Great interview about how an exercise physiologist makes use of a power meter.

http://www.srm.de/index.php/gb/srm-blog/science/566-leistung-im-radsport-aus-australischer-sicht-david-martin-ais-im-interview

Better reading than that train wreck of study linked above.

 

[CoachFergie]

Not posting in the power meter thread as Oldcoward is on my ignore list so I only see half of the thread. And the study in question is so laughable it's not worth discussing.

Evidence that a power meter does what it claims it does...

ABSTRACT
GARDNER, A. S., S. STEPHENS, D. T. MARTIN, E. LAWTON, H. LEE, and D. JENKINS. Accuracy of SRM and Power Tap Power
Monitoring Systems for Bicycling. Med. Sci. Sports Exerc., Vol. 36, No. 7, pp. 1252–1258, 2004. Purpose: Although manufacturers
of bicycle power monitoring devices SRM and Power Tap (PT) claim accuracy to within 2.5%, there are limited scientific data available
in support. The purpose of this investigation was to assess the accuracy of SRM and PT under different conditions. Methods: First,
19 SRM were calibrated, raced for 11 months, and retested using a dynamic CALRIG (50–1000Wat 100 rpm). Second, using the same
procedure, five PT were repeat tested on alternate days. Third, the most accurate SRM and PT were tested for the influence of cadence
(60, 80, 100, 120 rpm), temperature (8 and 21°C) and time (1 h at
300 W) on accuracy. Finally, the same SRM and PT were
downloaded and compared after random cadence and gear surges using the CALRIG and on a training ride. Results: The mean error
scores for SRM and PT factory calibration over a range of 50–1000 W were 2.3  4.9% and 2.5  0.5%, respectively. A second
set of trials provided stable results for 15 calibrated SRM after 11 months (0.8  1.7%), and follow-up testing of all PT units
confirmed these findings (2.7  0.1%). Accuracy for SRM and PT was not largely influenced by time and cadence; however, power
output readings were noticeably influenced by temperature (5.2% for SRM and 8.4% for PT). During field trials, SRM average and
max power were 4.8% and 7.3% lower, respectively, compared with PT. Conclusions: When operated according to manufacturers
instructions, both SRM and PT offer the coach, athlete, and sport scientist the ability to accurately monitor power output in the lab and
the field. Calibration procedures matching performance tests (duration, power, cadence, and temperature) are, however, advised as the
error associated with each unit may vary. Key Words: CALIBRATION, CYCLING, ERGOMETERS, VALIDITY

What do you know a power meter does what it claims. Wouldn't it be nice if all claims came with the same evidence!

 

[CoachFergie]

Highly amusing looking at the two "Seinfeld" threads watching people make claims about nothing and make claims of improvements that are nothing but smoke and mirrors.

Did a test yesterday for a woman wanting to know her maximum heart rate. In 1989 I did my first lab test. We used an old erg and measured heart rate and lactate. The wattage was just recorded to set the workloads for each ramp and lactate and heart rate were the two main variables in this test. Funny now I do the same test (ramp test) and only look at power.

For this lady I put a Powertap in as well to record power. She doesn't race or train with a power meter but I suggested that when she comes in to re test she won't see a change in maximum heart rate but if the training has been appropriate will see an increase in power. I did suggest seeing this was her first test that she will probably see an improvement in her second test just from learning the demands of the test.

She will test again in February but a rider with their own power meter essentially performs a specific test every time they ride the bike. If they see a change in their sustained power then we know the training is working. If we see a change in heart rate it can be confounded by a huge range of factors.

If a portable blood lactate measurement tool was available it would only tell us what is happening to blood lactate levels not what is happening in the cell.

So power is the only measure of actual performance that isn't confounded by energy levels, energy mix, motivation, wind, heat or cold. I had a woman want to pull the pin on Masters Worlds because she could crack 16 sec for 200m on her home track in cold and windy conditions. The only way I could reassure her was telling her that her power was still improving. At Worlds on an indoor track in warm conditions she was .1 off the world record and came away with 4 World Titles. Good thing her coach didn't confuse result measurements with performance measurements or she would have never gone.

 

[CoachFergie]

Sorry, replying this away from the Seinfeld thread.

I re-read the abstract of the cited paper and, as far as I can tell, it compares the same training program using either the power range or HR range of lactate threshold. So the question this raises is if the results are not significantly different, then why use an expensive PM rather than a relatively cheap HR monitor for training purposes?

Because this is not the only way the power meter is used as a measurement tool for racing and training.

I give riders training ranges that they should sit in. This is so I can quantify the training load so when riders perform in races I can measure performance and determine if the training ranges appropriately prepared a rider.

While I may give a rider a number (power or RPE for those without power meters) I also give a description of the intensity (Anaerobic Capacity = Individual Pursuit Pace) to help clarify things. Even when training indoors I find riders need more stimulation than just looking at a number. I watch Cycling DVDs. Hence my comments that the authors of both studies would have found the same result had they compared a group watching Family Guy and a group watching the Simpson. Perhaps because of the similarity of these two shows I should compare Simpson's and CSI.

In the Robinson study they used L4 as a training zone. This is the highest intensity range that heart rate could conceivably be used to determine intensity although cardiac drift could confound this if doing common L4 workouts like 2 x 20min efforts. In the Swart study they used L5 training zone and even though the workloads balanced out the distribution of power over those efforts was very different. Even when given instruction to ease into the target heart rate zone the heart rate group overshot the intensity while the power group hit their marks automatically. This known as heart rate lag.

This lag is why it is very difficult to prescribe L5 workouts and above by heart rate. L6 efforts are performed above VO2max and one of the checkpoints for achieving VO2max is attaining maximal heart rate so heart rate is not ideal for measuring any anaerobic efforts. One can use the heart rate monitor to gauge recovery from hard efforts. That is one of the reasons I still wear a heart rate strap when training and racing.

What I am saying is that rather than picking a paper apart, like any knowledgable coach or exercise physiologist should be able to do with any similar paper, design and conduct a scientific study that shows the average Joe the benefits of a PM. This is up to the likes of you, Coach Fergie, and Andrew Coggan because of your knowledge and expertise in this area.

The benefit of the Power Meter is that it measures power. Gardner et al (2004) showed this and I might add pointed out several potential issues that have shaped the design of power meters since then (calibration etc).

I checked the Powertap and SRM websites and all I see are testimonials from athletes and coaches. The Quarq Cinqo has neither testimonials nor scientific studies. So for three of the major players in the PM world, there is not a single scientific study to support the use of PM amongst them.

Vogt, Ebert, Abiss, Lim and Nimmerichter among others have all published studies showing how we can better assess the demands of cycling and track the training of cycling using a Powermeter.

A pity is the cool stuff is being done in Professional and National Teams and it's their dollar that drives the applied research but information stays in house for fear of giving away a competitive advantage. I was dropped from a power based study on a National team for just suggesting how cool it was that this type of research was happening. I am involved in several other little projects based around London Olympics and have to sign confidentiality agreements.

Again, don't get me wrong, I understand how and why PMs are used and I use one myself, I have communicated with my coach of 3 years on the basis of the results of my PM data, and have read both Hunter & Coggan's texts on the use of power in training and racing. I am a convert and don't need convincing on the benefits of using a PM. But I am also a scientist and do think that coaches and PM companies should work together to do something more scientific than testimonials and case reports.

A positive sign is that a lot more studies now provide a measure of changes in power as well as physiological changes like VO2max, lactate and other biochemical markers. Seems that people realise the difference between what is being measured and what you use to measure it.

 

[CoachFergie]

I see the Dixon study was raised again as evidence for training with an independent crank system.

Here is the abstract as the study was never published so we can't review it properly.

Physiological responses to training using PowerCranks TM on trained cyclists

Stephen J. Dixon, Michael F. Harrison, Kenneth A. Seaman, Stephen S. Cheung, and J. Patrick Neary University of New Brunswick, Fredericton, NB; Dalhousie University, Halifax, NS; University of Regina, Regina, SK

PowerCranksTM are cycling cranks that are independent of each other, requiring force application throughout the pedal stroke, theoretically increasing muscle recruitment and stimulus in the legs.

At a given power output why would there be any further muscle recruitment. We all know the difference between one leg and two leg cycling at a given wattage is that the one leg cycling requires greater recruitment on type IIa fibres but there is no extra recruitment of fibres. An independent cranking system will require different recruitment of muscle fibres.

This study examined the physiological adaptations to PowerCranks, and the time course of responses in maximal and submaximal cycling performance. Eight trained cyclists (35.1 ± 6.8 y) participated in 6 weeks of 100% immersion training using solely PowerCranks, consisting of approximately 8 h/week of aerobic and anaerobic (~80:20) cycling training. A continuous incremental cycling test to exhaustion (50 W increase every 2 min) was performed before and after the training program using normal cranks. In addition, 10 min of submaximal cycling (70% of VO2max wattage) were performed with both normal cranks and PowerCranks at an approximate cadence of 85 r/min, pre and post training.

VO2max increased 15.6% (58.1 ± 5.8 to 67.3 ± 6.6, p = 0.013).

No control group. Was it the cranks or the training stimulus?

Maximum power increased 11.6% (316.7 ± 25.8 to 358.3 ± 20.4, p = 0.011) following PowerCranks training.

No control group. Was it the cranks or the training stimulus?

In summary, our data suggest that PowerCranks increased maximal aerobic capacity and power in trained cyclists.

It in fact does no such thing. A bit like Robinson et al (2011) and Swart et al (2009) it shows that a training stimulus leads to physiological and performance adaptations.

Sperlich et al 2010, Williams et al 2009 and Bohm et al 2008 all used a control group and found no differences between a group training on independent cranks and a group training on normal cranks.

 

[CoachFergie]

Hmmmm another Aldo Sassi rider busting out the fixxie in the off-season...

http://ivanbassoofficial.com/article/ivan-gets-back-saddle

But of course just because Pro Tour Ride X uses a method or Coach of Pro Tour Riders Y advocates a certain training method isn't a sound rationale for everyone adopting that method. Is it!

 

[FrankDay]

Sigh.... but you brought it up. A little clarification for those with a little bit of an open mind.

I see the Dixon study was raised again as evidence for training with an independent crank system.

Here is the abstract as the study was never published so we can't review it properly.



At a given power output why would there be any further muscle recruitment. We all know the difference between one leg and two leg cycling at a given wattage is that the one leg cycling requires greater recruitment on type IIa fibres but there is no extra recruitment of fibres. An independent cranking system will require different recruitment of muscle fibres.

Well, if you had ever spent 5 minutes using the cranks you would understand what they mean. The cranks recruit underused muscles, the muscles involved in lifting the leg and crank to get the pedal up and over the top. Without the use of these additional muscles people cannot pedal the cranks. Until these additional muscles become aerobically adapted, people cannot ride the cranks for very long. That is part of the reason adaption and improvement usually takes 6 weeks or more.

No control group. Was it the cranks or the training stimulus?



No control group. Was it the cranks or the training stimulus?

If you understood study design you would understand these riders acted as their own controls. Without a control group I don't think they would have been able to do their statistical analysis. The study design had these racers commence the PC period at the end of their racing season when they expected their fitness to be at a maximum and where they would usually expect to see a drop in performance. Instead they saw an increase. It may not be optimum but it is what they did. It was good enough to be selected for an oral presentation at the Canadian Exercise Physiologist National convention.

It in fact does no such thing. A bit like Robinson et al (2011) and Swart et al (2009) it shows that a training stimulus leads to physiological and performance adaptations.

Huh? Their data did show a statistically significant increase in both VO2max and max power. Why isn't that support their conclusion.

Sperlich et al 2010, Williams et al 2009 and Bohm et al 2008 all used a control group and found no differences between a group training on independent cranks and a group training on normal cranks.

The difference here was Dixon actually followed our instructions and used an immersion protocol compared to all the other studies out there so far which use part time use. Details do matter in interpreting this stuff. The difficult part of a study is not in performing the study but in interpreting the results.

If someone is really interested in "proving" that our claims are all hogwash and the cranks do nothing I would really suggest that they use a protocol that at least follows our instructions for best use.

 

[CoachFergie]

Well, if you had ever spent 5 minutes using the cranks you would understand what they mean. The cranks recruit underused muscles, the muscles involved in lifting the leg and crank to get the pedal up and over the top. Without the use of these additional muscles people cannot pedal the cranks. Until these additional muscles become aerobically adapted, people cannot ride the cranks for very long. That is part of the reason adaption and improvement usually takes 6 weeks or more.

They say increased muscle recruitment not utilising different muscles.

But in the Luttrell, Knuckles, Bohm and Fernandez-Pena studies 6 weeks was sufficient to see a physiological change.

If you understood study design you would understand these riders acted as their own controls. Without a control group I don't think they would have been able to do their statistical analysis.

I don't think I am the one who needs to brush up on study design. A paired t-test between pre and post training will give you the results supplied.

Controlled themselves, classic. Can see why the study was never published. Think even Journal of Strength and Conditioning Research wouldn't bother with that.

Instead they saw an increase. It may not be optimum but it is what they did.

.

No control and no way of proving if the cranks played any role in the change or whether it was all down to the training performed.

It was good enough to be selected for an oral presentation at the Canadian Exercise Physiologist National convention.

But not published.

Huh? Their data did show a statistically significant increase in both VO2max and max power. Why isn't that support their conclusion.

Because they can't show what caused the change. Was it the cranks or the training. 3 other studies published in sports science and applied physiology journals used a control and found no difference between an experimental group and a control.

The difference here was Dixon actually followed our instructions and used an immersion protocol compared to all the other studies out there so far which use part time use. Details do matter in interpreting this stuff. The difficult part of a study is not in performing the study but in interpreting the results.

If it was so easy they should have used a control group.

If someone is really interested in "proving" that our claims are all hogwash and the cranks do nothing I would really suggest that they use a protocol that at least follows our instructions for best use.

Yes, very realistic to expect someone to use an independent crank exclusively for 6-9 months.

It's a ****ty study and adds nothing to the debate. No control so no way of telling what caused the changes.

"Controlled themselves"

 

[Tapeworm]

But if you're a pro who uses independent cranks, even if it's on bike hanging in the garage, then the training effect (from an unknown period of time using them) is indisputable.

 

[blutto]

I see the Dixon study was raised again as evidence for training with an independent crank system.

Here is the abstract as the study was never published so we can't review it properly.



At a given power output why would there be any further muscle recruitment. We all know the difference between one leg and two leg cycling at a given wattage is that the one leg cycling requires greater recruitment on type IIa fibres but there is no extra recruitment of fibres. An independent cranking system will require different recruitment of muscle fibres.





No control group. Was it the cranks or the training stimulus?



No control group. Was it the cranks or the training stimulus?



It in fact does no such thing. A bit like Robinson et al (2011) and Swart et al (2009) it shows that a training stimulus leads to physiological and performance adaptations.

Sperlich et al 2010, Williams et al 2009 and Bohm et al 2008 all used a control group and found no differences between a group training on independent cranks and a group training on normal cranks.

...apart from the lack of a control group, what procedural issues does the Dixon study have that would make it invalid...

Cheers

blutto