What is the evidence that training with power is superior to . . .

rmur17

speed is a reasonable measure against a fixed trainer load as long as you try to control the variables I mentioned + whatever I forgot. slightly ot but this year I've had to extend the length of my standard workout/test CT courses for ~20min, and ~30min as the old ones had simply gotten too short somehow .

The CT is a great tool - I have to say the main reason I bought it was for power feedback though having experienced ergo mode I'd say that's something else I'd much rather not do without.

__________________
rmur

RChung

Why do you keep misrepresenting the findings? Wait ... don't bother answering that. I already know.

1. The study did show a change in the pattern of force application, and a change in exactly the way that PCs are supposed to elicit. Congratulations. They work!

2. Despite your claim that new PC users ought to regress in their power output, in fact they increased their power output. Congratulations, again!

3. Alas, the non-PC group increased their power output by the same amount. Uh oh.

The conclusion? PCs change pedaling behavior exactly as intended -- and the intended change has no effect on power output.

Fday

Huh?
1. Showing a change in force application. That starts from the first ride. BFD. It takes more than a simple change in force application to increase power. It takes actual increase in force application.

2. New PC users do regress in power output when using PC's, but usually not when using regular cranks. Most studies, including this one, test people on regular cranks. No surprise again.

3. So, it takes a little more time to see increased power. Ask almost any PC'er. The changes necessary to see benefit are several and seemingly, based upon this study, take more than the 10 uses in 5 weeks studied here and less than the 18 uses in 6 weeks showing positive effect studied by Luttrell.

4. The PC's behaved exactly as intended but the stimulus was not great enough to exact a statistically significant change. Would you expect such a demonstrable benefit after 10 rides after giving someone a power meter? Power improvement does not come easily.

My claims require 6-9 months of exclusive use for users to see my claimed benefits. You criticize them as being ineffective following one study that looked at 10 uses. LOL

You guys really reach for reasons to slam the PC's. What is your problem? LOL

This particular study is valuable because it says if you don't use them enough you can't expect to see benefit. Something we have said from, almost, the beginning. (Actually, in the beginning I thought part-time use would be optimum, I was wrong.) Now we know a number below which people cannot expect to see benefit, at least in 5 weeks.

Alex Simmons

I doubt anyone has a problem. It's probably because your claims are so far-fetched that your own reach* is ridiculously long.

* i.e. claims of efficacy in raising a rider's sustainable power, versus simply riding normal cranks

__________________
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http://www.cyclecoach.com/

RChung

Hmmm. Haven't you been saying that the six week Luttrell and Potteiger study show that PCs work? What is the magic that happens between five weeks and six?

Fday

Well, to be truthful, as I always try to be, I was surprised that the Luttrell study was as positive as it was in only 6 weeks of 3 x/week use. But, the numbers were what they were. Further, the Dixon study got very postive results in only 6 weeks. So, it is becoming clear to me that 6 weeks is plenty of time for most to start to see improvement.

What was the difference. Well Luttrell had the people on the bike 60 minutes 3 times a week and the Dixon study had the participants in an immersion program for 6 weeks. This compared to the bohm study which was two sessions a week using some crazy 3 minute interval set (it is not clear to me what they really did but it seems clear there was no attempt to develop any endurance). Further, the bohm study did not use trained cyclists, nor trained anything. "Because previous studies showed that the grade of physiological fitness has no effect on motive efficiency (Sanderson 1991), no emphasis was placed on the proficiency level of the subjects participating in the study." Where, both Luttrell and Dixon required the participants to be trained cyclists. Perhaps the difference can be explained by this difference.


So, there is not any magic between 5 and 6 weeks. The difference seen, is, in my opinion, a matter of intensity and perhaps in study design. Whenever you have a study it is important to understand the details in order to fully understand the results and possibly the differences seen in other studies. If you had taken the time to carefully read these it is possible you might have come to these same conclusions on your own, although it might have been more helpful to you in interpreting these differences if you had any experience with them.

swampy1970

Hey, you forgot riding on the training into a headwind, which is what I seem to do all the time.

... oh, and way too take something humorously simple and make it overly complicated. I guess after this train wreck of a thread I shoulda expected it.

Muss? Sounds like someone needs to see a Doc!

RChung

Hmmm. Well, I'd agree that "whenever you have a study it is important to understand the details in order to fully understand the results." I'd say one of the most important study design details to understand with the Dixon study is that it had no control group. Yes, they saw improvement in the PC group. The Bohm study also saw improvement in their PC group. The difference is, the Bohm study had a control group and the controls improved by the same amount.

swampy1970

The magic is that you're probably able by 6 weeks to actually ride for an hour straight at an rpm that people would call worthy of training.... Well, that was the case for me anyway. I only managed my first 90rpm session not too long ago and I bought the damn things in November.

fergie

The magic thing I have learned from coaching since 1992 is that the effects of training are very specific.

For my 3000m event run on a very fast indoor track with tight bends and temperature around 20degrees I have to do very specific intervals to make the best progress.

Intervals on the hills don't cut it as my position changes and I can't replicate the cadence.

Intervals behind a motorbike don't cut it as my cadence is now too high and power is far lower.

Intervals on my local track don't cut it as it's a outdoor concrete track, is very slow, very exposed and has bends that are far easier to ride and keep the power on.

Intervals on the road don't cut it as my position changes.

Intervals on the rollers don't cut it as I spin out too quick and don't come close to target power.

So how is using a piece of equipment that changes how I pedal from how I intend to pedal when racing going to help me ride a faster pursuit?

__________________
Hamish Ferguson: Cycling Coach
http://hamishferguson.blogspot.com/

acoggan

Are you saying that Frank has mental problems?

Fday

Actually, the Dixon group did have a control group, just not a typical one. I ran across the protocol they sent me when they proposed the study. The idea was to take these trained people and initially test them at the end of the season, when it would be expected that their fitness would be maximum, and after which, one would expect their fitness numbers to fall, not increase. They then did the immersion training on the PC's (it would have been hard to get participants if people were training for upcoming races to go "exclusive" PC) and then re-testing.

It may not be perfect as control groups go, but the rational is reasonable and it did allow them to calculate statistical significance.

As I said, the Bohm group may have seen equal increase in both groups because they didn't study trained cyclists. So, both groups simply saw training effect and there wasn't enough time to separate out any separate PC effect. If they had chosen trained cyclists (as the Luttrell study did) it is probable that the control group would have seen less improvement since the study stimulus would probably not be much more than they are/were used to doing. In the Luttrell study the control group also saw improvement, it was just a lot less than the PC group and never reached statistical significance (the control group HR dropped 5 bpm in the post test whereas the PC group dropped 15 bpm) .

Fday

There would be no advantage to using a piece of equipment that makes you do something other than what you "intend" to do in a race. The reason that people get power cranks is they believe that there is a more efficient way of pedaling and PC's can help them achieve that. So, people get PC's because they intend to pedal "better" when racing.

If you "intend" to pedal as you are now then don't get PC's because they will change you. However, if you believe there might be some room for improvement and you would like a little help, then you should consider PC's.

swampy1970

Way to miss the point. You are supposed to pedal the same on regular cranks after training on PowerCranks - or should I say you spend nearly all of your time on PowerCranks and then go race on your lovely stiff Dura Ace/Record/whatever....

... that I've yet to actually ride on a set of traditional cranks after putting my PowerCranks on (apart from putting the PC's in lockout mode when riding down the bike path with my 5 year old daughter and once just to ride up hill for comparison) I can't pass on my acendotal evidence as to what the scoop is riding for an extended period of time with regular cranks after months on PC's.

May I ask how seriously you take your pursuiting?