PowerCranks Study -- The Journal of Strength and Conditioning Research: Vol. 17, No. 4, pp. 785–791

Triathlon Forum
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Looking for more on the study Frank is reporting on I found this. Yes I have a Master’s in Statistics but Im tired and dont understand all this fitness stuff and don’t feel like reading but I thought others would. This study has a control group.

Effects of Short-Term Training Using Powercranks on Cardiovascular Fitness and Cycling Efficiency
Mark D. Luttrell,a and Jeffrey A. Potteigerb, c

aDepartment of Health, Sport and Exercise Science, University of Kansas, Lawrence, Kansas 66045

bDepartment of Physical Education, Health and Sport Studies, Miami University, Oxford, Ohio 45056-3491

cAddress correspondence to Dr. Jeffrey A. Potteiger, E-mail: potteija@muohio.edu

ABSTRACT

Powercranks use a specially designed clutch to promote independent pedal work by each leg during cycling. We examined the effects of 6 wk of training on cyclists using Powercranks (n = 6) or normal cranks (n = 6) on maximal oxygen consumption (O2max) and anaerobic threshold (AT) during a graded exercise test (GXT), and heart rate (HR), oxygen consumption (O2), respiratory exchange ratio (RER), and gross efficiency (GE) during a 1-hour submaximal ride at a constant load. Subjects trained at 70% of O2max for 1 h·d−1, 3 d·wk−1, for 6 weeks. The GXT and 1-hour submaximal ride were performed using normal cranks pretraining and posttraining. The 1-hour submaximal ride was performed at an intensity equal to approximately 69% of pretraining O2max with O2, RER, GE, and HR determined at 15-minute intervals during the ride. No differences were observed between or within groups for O2max or AT during the GXT. The Powercranks group had significantly higher GE values than the normal cranks group (23.6 ± 1.3% versus 21.3 ± 1.7%, and 23.9 ± 1.4% versus 21.0 ± 1.9% at 45 and 60 min, respectively), and significantly lower HR at 30, 45, and 60 minutes and O2 at 45 and 60 minutes during the 1-hour submaximal ride posttraining. It appears that 6 weeks of training with Powercranks induced physiological adaptations that reduced energy expenditure during a 1-hour submaximal ride.

Reference Data:Luttrell, M.D. and J.A. Potteiger. Effects of short-term training using Powercranks on cardiovascular fitness and cycling efficiency.

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Better get Frank, Andrew and those guys over here. They are arguing again over in another thread

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My moniter is getting warm, here it comes…

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FWIW, this study seems to have been published in 2004 & is not the same one Frank is argueing with others about in the other thread. ;-p

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I know its not the same but it did have a control group which seems to be the big issue with the other abstract.

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We’ve gone over this one. It showed increased efficiency, but not absolute performance.

Efficiency is a good first step toward improved performance, but increased efficiency does not necessarily lead to increases in sustainable power. The performance claim has not yet been shown with any control groups, as far as I know. There are many ways to improve the efficiency of cyclists. The most well-known is to have them decrease cadence. The efficiency gains reported here are consistent with reducing cadence. I know there was a dust-up over whether these authors controlled for cadence. Frank said they did, but couldn’t point to evidence. Somebody else said they didn’t. Since almost all PC users reduce their cadence, the cadence issue clouds this study. I still don’t know if they controlled for cadence. Does anyone have access to the full report?

Importantly – it is performance that Frank claims on his website and here and everywhere else. Efficiency doesn’t win races. Power wins races. Burning calories efficiently is good; burning them faster is better.

Frank claims a 40% improvement in power. That has never been demonstrated in a controlled trial.

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Frank claims a 40% improvement in power.

Serious question: Does he still have that claim in his website?

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Serious question: Does he still have that claim in his website?

From “The Story” link:

“Frank’s training interest in PowerCranks™ was further piqued by his documented 38% improvement in his own power after less than 6 months of use.”
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