As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists"

Nov 3, 06 13:44

Post #1 of 147 (9516 views)

Stephen J. Dixon, Michael F. Harrison, Kenneth A. Seaman, Stephen S.Cheung and J.Patrick Neary. University of New Bruswick, Fredericton, NB; Dalhousie University, Halifax, NS; University of Regina, SK , presented at the Canadian Society for Exercise Physiology (CSEP) Nov 3, 2006

Physiological responses to training using PowerCranks on trained cyclists

ABSTRACT

PowerCranks? 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. This study examined the physiological adaptions to PowerCranks, and the time course of responses in maximal and submaximal cycling performance. Eight Trained cyclists (35.1 � 6.8 yr) participated in 6 weeks of 100% immersion training using solely PowerCranks, consisting of ~8 h/wk of aerobic and anaerobic (~80:20) cycling training. A continuous incremental cycling test to exhaustion (50 W increase every 2 min) was performed prior to and following 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 rpm, pre and post training. VO2max increased 15.6% (58.1 �5.8 to 67.3 � 6.6, P=0.013), Maximum power increased 11.6% (316.7 � 25.8 to 358.3 + 20.4, P=0.011) following PowerCranks training. In summary, our data suggest that PowerCranks increased maximal aerobic capacity and power in trained cyclists.

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 13:45

Post #2 of 147 (9506 views)

What did the control group do?

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Ashburn] [ In reply to ]

Nov 3, 06 13:50

Post #3 of 147 (9485 views)

In Reply To:

What did the control group do?

You took the words right out of my mouth.

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 13:52

Post #4 of 147 (9469 views)

In Reply To:

Stephen J. Dixon, Michael F. Harrison, Kenneth A. Seaman, Stephen S.Cheung and J.Patrick Neary. University of New Bruswick, Fredericton, NB; Dalhousie University, Halifax, NS; University of Regina, SK , presented at the Canadian Society for Exercise Physiology (CSEP) Nov 3, 2006

Physiological responses to training using PowerCranks on trained cyclists

ABSTRACT

PowerCranks? 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. This study examined the physiological adaptions to PowerCranks, and the time course of responses in maximal and submaximal cycling performance. Eight Trained cyclists (35.1 � 6.8 yr) participated in 6 weeks of 100% immersion training using solely PowerCranks, consisting of ~8 h/wk of aerobic and anaerobic (~80:20) cycling training. A continuous incremental cycling test to exhaustion (50 W increase every 2 min) was performed prior to and following 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 rpm, pre and post training. VO2max increased 15.6% (58.1 �5.8 to 67.3 � 6.6, P=0.013), Maximum power increased 11.6% (316.7 � 25.8 to 358.3 + 20.4, P=0.011) following PowerCranks training. In summary, our data suggest that PowerCranks increased maximal aerobic capacity and power in trained cyclists.

Can you tell us what happened to their submaximal efficiency/economy, Frank? (I'm struck by the fact that they chose to focus on changes in VO2max instead.)

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Ashburn] [ In reply to ]

Nov 3, 06 13:54

Post #5 of 147 (9453 views)

You will have to ask the authors. All I have is the abstract. However, since the results are statisitcally significant I suspect that the control group didn't do as well and if they improved their VO2max 15% (or anyhere near that amount) I would doubt the results as being valid.

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 13:57

Post #6 of 147 (9437 views)

In Reply To:

You will have to ask the authors. All I have is the abstract. However, since the results are statisitcally significant I suspect that the control group didn't do as well and if they improved their VO2max 15% (or anyhere near that amount) I would doubt the results as being valid.

So there was in fact a control group?

Why would you question the validity of a 15% change in VO2max? Even world class cyclists frequently show 10% changes in VO2max in/out of season, and their minimal training load is undoubtly considerably greater than the starting point for the individuals in this study.

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Andrew Coggan] [ In reply to ]

Nov 3, 06 14:01

Post #7 of 147 (9408 views)

[reply]Can you tell us what happened to their submaximal efficiency/economy, Frank? (I'm struck by the fact that they chose to focus on changes in VO2max instead.)[/reply]

No, all I have is the abstract. I would love to see the raw data. I will comment that it would appear these results are seemingly in some conflict with the Luttrell data. Luttrell showed an efficiency improvement of 10% in 6 weeks and while Dixon shows an 11% improvement in power in 6 weeks, it would seem that efficiency has actually dropped with a 15% increase in VO2max during the same period.

I do know that the subjects were apparently quite experienced cyclists (pro/cat 1 level) so I would certainly think that these results, if confirmed, put to rest the theory put forth by many that cycling power is centrally limited.

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 14:06

Post #8 of 147 (9387 views)

In Reply To:

it would appear these results are seemingly in some conflict with the Luttrell data. Luttrell showed an efficiency improvement of 10% in 6 weeks and while Dixon shows an 11% improvement in power in 6 weeks, it would seem that efficiency has actually dropped with a 15% increase in VO2max during the same period.

Not necessarily: their efficiency may have remained constant, or even improved, but their power didn't go up as much as their VO2max did due to a reduction in anaerobic capacity.

In Reply To:

I do know that the subjects were apparently quite experienced cyclists (pro/cat 1 level)

Huh...based on the age of the subjects, their low initial VO2max, and just the nature of the study I would have assumed it was a sample of convenience (e.g., grad students).

In Reply To:

so I would certainly think that these results, if confirmed, put to rest the theory put forth by many that cycling power is centrally limited.

??

The data don't show that in any way, shape, or form.

Last edited by: Andrew Coggan: Nov 3, 06 14:09

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Andrew Coggan] [ In reply to ]

Nov 3, 06 14:07

Post #9 of 147 (9376 views)

[reply][reply]
You will have to ask the authors. All I have is the abstract. However, since the results are statisitcally significant I suspect that the control group didn't do as well and if they improved their VO2max 15% (or anyhere near that amount) I would doubt the results as being valid. [/reply]

So there was in fact a control group?

Why would you question the validity of a 15% change in VO2max? Even world class cyclists frequently show 10% changes in VO2max in/out of season, and their minimal training load is undoubtly considerably greater than the starting point for the individuals in this study.[/reply]

Why would I doubt the results if the control group increased similarly? I don't think world class cyclists (or anyone other than perhaps rank beginners) would increase their VO2 max 15% in 6 weeks on 8 hr/week training which was what this protocol was apparently.

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 14:08

Post #10 of 147 (9363 views)

please tell me there was a control group. because if there was not, this would be nearly useless data.

all it would show (from what i can gather from the abstract) is that focused training can increase fitness.

and i dont think that is real big news.

Where would you want to swim ?

Last edited by: GregX: Nov 3, 06 14:22

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Andrew Coggan] [ In reply to ]

Nov 3, 06 14:09

Post #11 of 147 (9356 views)

[reply]So there was in fact a control group?[/reply]

I don't know that for a fact but I don't know how you calculate statistical significance without one.

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 14:10

Post #12 of 147 (9347 views)

I guess I'll bite!!!

That means about the same thing as my experiment!!

In preparation for the 2006 racing season, in Nov to end of Dec 2005, with 8 weeks of riding my windtrainer and documenting my HR and watt output, I increased my wattage output by nearly 11% and dropped my HR by 8%. Now what does that mean?? It only means I had a concentrated workout of approx 4hr's per week on my windtrainer and made the above improvements, in the off-season when my initial condition was at a lower level then during the racing season. Unless that test was done in mid-season, when an athlete is close to his peak AND you see those improvements, THEN it may mean something. The results are dependent on the time of year, fitness of the athlete at start of experiment, level riding during the experiment, etc.

Short sound bites are catchy, but have little meaning.

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 14:12

Post #13 of 147 (9330 views)

Quote:

Also, I think you underestimate the changes that occur. For the naysayers I recommend that you practice typing the word: impossible. :-) Stand by to be amazed.

You gotta be kidding us.

----------------------------------
"Go yell at an M&M"

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 14:12

Post #14 of 147 (9329 views)

uh, frank, you did you take statistics, right?

(they may have done it by looking at perfomance at start of study vs. end of study).

Where would you want to swim ?

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 14:13

Post #15 of 147 (9328 views)

In Reply To:

Why would I doubt the results if the control group increased similarly? I don't think world class cyclists (or anyone other than perhaps rank beginners) would increase their VO2 max 15% in 6 weeks on 8 hr/week training which was what this protocol was apparently.

Aren't we getting ahead of ourselves with all of this? If there was no control group, then it is quite impossible to say that the improvements were not due simply to a supervised training program. That is easy to elicit. Ask any coach.

Was there a control group who were subjected to a similar training load, but on regular cranks? It's a yes or no thing.

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 14:13

Post #16 of 147 (9327 views)

In Reply To:

I don't think world class cyclists (or anyone other than perhaps rank beginners) would increase their VO2 max 15% in 6 weeks on 8 hr/week training which was what this protocol was apparently.

That would entirely depend upon their initial state of training (as you acknowledge) as well as the intensity of the training program. For example, an intially untrained person might see a 10% increase in VO2max in just 10 d provided that the training is strenuous enough. These individuals (EDIT: in the Dixon study) weren't "rank beginners", but then again they weren't exactly highly trained, either (esp. if they were in fact pro/cat. 1 riders, in which case their initial VO2max of <60 mL/min/kg suggests that the study started after they had just spent a month or so completely off the bike).

Last edited by: Andrew Coggan: Nov 3, 06 14:16

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 14:13

Post #17 of 147 (9319 views)

In Reply To:

I don't know that for a fact but I don't know how you calculate statistical significance without one.

Doink!

You're not serious, right?

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Andrew Coggan] [ In reply to ]

Nov 3, 06 14:15

Post #18 of 147 (9307 views)

[reply]Huh...based on the age of the subjects, their low initial VO2max, and just the nature of the study I would have assumed it was a sample of convenience (e.g., grad students). [/reply]

Early on they gave us a list of subjects which included one pro, several CAT 1 cyclists, and several very elite age group triathletes. One of the posters here told me he knew two of the participants in the study and told me they were quite capable before the study and are more capable now.

Further, this group is quite experienced and well known. they don't do shoddy work to my knowledge. Another group out of Australia is doing a similar study and we expect data collection to be done on that study about the end of the year.

Frank

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Andrew Coggan] [ In reply to ]

Nov 3, 06 14:16

Post #19 of 147 (9288 views)

[reply]That would entirely depend upon their initial state of training (as you acknowledge) as well as the intensity of the training program. For example, an intially untrained person might see a 10% increase in VO2max in just [i][b]10 d[/b][/i] provided that the training is strenuous enough. These individuals weren't "rank beginners", but then again they weren't exactly highly trained, either (esp. if they were in fact pro/cat. 1 riders, in which case their initial VO2max of <60 mL/min/kg suggests that the study started after they had just spent a month or so completely off the bike).[/reply]

You are assumng they are all male. I don't believe they were.

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Frank,
An original Ironman and the Inventor of PowerCranks

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Ashburn] [ In reply to ]

Nov 3, 06 14:18

Post #20 of 147 (9276 views)

Was there a control group who were subjected to a similar training load, but on regular cranks? It's a yes or no thing.

Cut Frank a break, he doesn't know anything other than what is in the abstract. Hopefully he'll get a copy of the full paper and post a link for us.

Swimming Workout of the Day:

Favourite Swim Sets:

2020 National Masters Champion - M50-54 - 50m Butterfly

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [polarbear] [ In reply to ]

Nov 3, 06 14:19

Post #21 of 147 (9269 views)

Mr. Polarbear.

Your results are anecdotal. These are part of a systematic study with reported statistical significance to the results. There is no comparison.

--------------
Frank,
An original Ironman and the Inventor of PowerCranks

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 14:20

Post #22 of 147 (9261 views)

In Reply To:

Early on they gave us a list of subjects which included one pro, several CAT 1 cyclists, and several very elite age group triathletes.

Not by name, I hope?!?

In Reply To:

Further, this group is quite experienced and well known. they don't do shoddy work to my knowledge.

Failure to include a control group would clearly be a weakness, but I certainly wouldn't go so far as to label it "shoddy work".

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 14:22

Post #23 of 147 (9254 views)

In Reply To:

[reply]That would entirely depend upon their initial state of training (as you acknowledge) as well as the intensity of the training program. For example, an intially untrained person might see a 10% increase in VO2max in just [i][b]10 d[/b][/i] provided that the training is strenuous enough. These individuals weren't "rank beginners", but then again they weren't exactly highly trained, either (esp. if they were in fact pro/cat. 1 riders, in which case their initial VO2max of <60 mL/min/kg suggests that the study started after they had just spent a month or so completely off the bike).[/reply]

You are assumng they are all male. I don't believe they were.

You are correct, and I am ashamed.

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [More is MORE] [ In reply to ]

Nov 3, 06 14:26

Post #24 of 147 (9240 views)

My only response to this is Frank opened himself up to this by posting only an abstract. This is an abstract in which sounds like he limited idea of what was going on during the study. If he is going to tout this as "proof" of PC's performance enhancing capabilities, he may have jumped the gun.

Demps

Re: As promised "Physiological responses to six weeks of training using PowerCranks on trained cyclists" [Frank Day] [ In reply to ]

Nov 3, 06 14:27

Post #25 of 147 (9225 views)

How could there not be a control group? But then again, in alot of the abstracts that I read, it almost always references the improvements over a control group instead of "our data suggest that PowerCranks increased maximal aerobic capacity and power in trained cyclists" which has no reference whatsoever. - E

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