Powercranks - yes or no?

A light bike doesn't replace good fitness.

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ras11
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by ras11

I've had PCs for many years. I would recommend them, but carefully.

They are a training tool with some factional benifit. What Frank Day claims is generally accepted not to be true, and I would agree.

They are very stressful on hip flexors and lower back if you are not careful. And, my theory is, the source of many people's accolade, if their body types are weak in these areas. I believe in pedaling power is rooted in core stability, and PC's can address some of those weaknesses. If you are already well adapted and well rounded in strength, they might not have any effect for you at all, and could hamper your training.
:-) Toys-R-Us

Magellan3000
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by Magellan3000

Yeah, it is my first post. I only found this web site two days ago. I've looked at Cycling Forums off and on for years, rarely actually posted. Found Slow Twitch a couple of months ago. What can I say: I'd rather work out than talk about training.

As for data, I did a 20 minute power test I did last year. I also did a direct measure VO2Max test around that time. I don't train with power, but I do train with HR zones based upon that 20 minute test. I will post another power test update when I next do one which I expect to be either end of April or the second week of May. I will also post a direct measure VO2Max test then along with comparison to the previous one (done at George Washington University Exercise Physiology Lab).

It is unfortunate that I have to rely on subjectivity. I want to get a power meter, but I won't until I can get pedal-based ones. In the meantime, my subjective heuristics include (1) bury myself for 2 x 20 or 3 x 20 a couple of times per week, (2) almost bury myself for 1-2 hours continuously a couple of time per week. (3) recover adequately between these, (4) do a monster ride on the weekend at my IM race pace. The main thing I lose in following this heuristic is the ability to measure noise to 17 decimal places.

Tapeworm wrote:You make this is your first post??

Unfortunately a lot of what you mentioned about being "forced" to work certain muscles etc is so utterly subjective. Just because it feels hard doesn't mean it's beneficial. Do you have any actual data about how much this has helped? Powerfiles? Lactate readings? Or do you just "feel" like they are working?

Because there have been several studies now, all show the same thing, no improvement or sometimes even going backwards.

But great if they make you "feel" faster.

Magellan3000
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by Magellan3000

I can't imagine spinning them at 120rpm for any length of time. You are my hero if you can pull that off. On regular cranks, I keep it under 110, max. Will give extended 120 RPM sets try though and post how that works out...

Bordeaux wrote:
LarsEjaas wrote:I actually like the Powercranks (flame away!!!). My economy on the bike is slowly improving (I can't say that it wouldn't have without the cranks, so this is no way scientific). BUT my economy was measured at 24% at my last test and I think it has to do with the Powercranks training.

The trick is to get them incorporated in your training... I have a set on a bike I only use for this - year round. At this time of the year I actually only do a little riding inside on rollers on them. I ride 15-20 min. before or after the training.
I then concentrate on high cadence (around 110-120 rpm). This is a great way of keeping my pedaling smooth.

When my cyclocross-season is finished in a week I will then start riding a bit more on them, taking them outside for some tempo-rides.
In my racing season I will do recovery-rides on these, riding with a high cadence for around 1½ hours. BUT it has taken years for me to be able to ride easy on these! Just looked in my training software: I have ridden around 26.000 km. on the cranks during the last 3 years. I think the hard thing was to avoid getting REALLY heavy legs from the PC riding in the beginning - this kind of training can make you sore for weeks if you aren't carefull.


Flame on.....

How do you measure efficiency?

Any chance of you putting a video on you tube of you reving at 120 rpm, using power cranks, for more than say 5 minutes? i would be interested to see it.

I had some PCs for a few months. My opinion was tha they were pretty pointless. I was trying to develop a set muscles for endurance that are just not designed for that sort of work.

I had no problem using them technically, just that after 60 seconds of reving at 120rpm my hip flexors said "no more". Such a small muscles is not for lifting repeatedly.

I did some long rides on them, perhaps 150Kms being the longest, but the cadence would always be very low.

Anyone who doubts this could try this simple exercise: Whilst standing up, try lifting one of your feet, 345mm off the floor and putting back on the floor. Repeat 120 times in a minute, then keep going. This would simulate the effect of a power crank, producing no forward force, just simply not producing negative torque, whilst supplying 100% of your available "exercise oxygen" to the lifting muscles. That is without having the weight of a pedal and crank attached to your foot.

One thing that the PC did teach me is that we do not, at any cadence above say 60, add positive torque to the pedaling action by pulling up (ecept maube for a very short burst of a second or so) and that it is pointless trying to do so. Better just to push hard.

Magellan3000
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by Magellan3000

Your post intrigued me so I got the Coyle paper which I think you are referring to: "The pedaling technique of elite endurance cyclists: changes with increasing workload at constant cadence." My observations:

(1) The study did not examine role of power asymmetry. Has any study looked at left/right asymmetry amongst elite riders?

(2) The study did not look at (seated) climbing. Many cyclists remember the first time they did seated climbing using clip-in pedals. They started using their hamstrings... and found another gear.

(3) The study conclusions include: "The importance of the upstroke at the high workload was that, by decreasing the negative torque, the cyclists effectively decreased the work that must be done during the downstroke of the other leg, thereby doing less positive work for the same power output. The positive work done during the downstroke was 98.6% at the low workload and 96.3% at the high workload. Although elite subjects were able to reduce the work requirements of one leg during the downstroke by eliminating negative torque production or by producing some slight positive torque during the upstroke with the other leg, they did not use a strategy of producing significant positive work during the upstroke at the higher workload. Thus there is little evidence that feedback devices used to increase pulling up during the upstroke (e.g., Briggs et al., 1989) would help improve the performance of elite cyclists. Nevertheless, since the amount of negative torque produced during the upstroke by the elite subjects in our study appeared significantly less than the amount produced by less skilled subjects in other studies (Lafortune and Cavanagh, 1983; Ericson & Nissel, 1988), it is possible that less skilled cyclists might benefit from learning to reduce negative torque during the upstroke, without attempting to pull up significantly." <= So the study says 'elites unload the recovery leg on the upstroke' and notes another study which showed less skilled riders fail to do so. What about the rest of us duffers? How do we duffers get from creating negative force on the recovery to unloading like the elites? I suppose 38 hour training weeks are sure to do it... eventually... the main problem is: I don't have 38 hours a week to get there.

(4) "the ergometer was equipped with a racing style seat and drop handlebars. Both items were then adjusted to match the characteristics of each cyclist's bicycle." <= sounds like the geometry was set up to mimic a normal road bike; not a time trail setup. They make no mention of the use of aero bars, so I assume none was used. They make no mention about what riding position riders took. Did subjects merely stay in the drops or were they asked to get lower as they would during a time trial demanding competition-like aerodynamics? This seems like a real weakness in the study. Do elites unweight their recovery leg even when in full aero position? It is not at all clear from the study. Yet there is a world of difference between being in these two postions, especially when it comes to unloading the recovery leg. Don't think so? Go out on your bike. First, get in the drops and try single leg drills. Next, get in aero postion and try single leg drills. The load on your hip flexor will be greatly increased... making unloading the recovery leg much more difficult.

devinci wrote:I found a link relating Dr Ed Coyle research on the subject. Not quite the link I was looking for, but have a read, especially the paragraphs above figure 1 and below it.

http://www.bicycle.net/2007/pedaling-technique-basics

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Tapeworm
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by Tapeworm

Whilst it is good you're looking into all of this it has all been discussed ad naseum by many different people who have a great deal of knowledge of such things.

And it simply come down to this, out of all the studies done to date there has been no demonstrable benefit to using powercranks or single leg drills. The closest thing to any benefit by single leg drills are those which use a counterweight on the opposite crank arm - they showed a clear improvement to the oxidative capacity if the muscles HOWEVER this still didn't yield a performance benefit.

Also the counterweight drills show clearly how unessecary any "unweighting" of the pedal really is.

Further studies by Jim Martin (using the Coyle study as a reference) showed that actually a lot of elite riders produced more negative torque than amateurs and that this negative torque was in line with the expected weight of the leg.

One aspect people seem to fail to grasp is that the body is a system. To produce power to propel the bike forward you cannot magically bypass the limitation of the body as a whole. Thus by suddenly using slightly different muscles you cannot create more power than you are capable of. Cardiovascular, thermal, mitochondrial etc are all parts of the system. If you want to use powercranks to pedal then go ahead but you can't suddenly get more power because of it.

Whilst there are hints and possibilities that you may get a few extra watts from weight training, drinking beetroot juice or inertia loaded single legs drills at the end of the day the clearest and proven way to improve is to ride. A lot. Sometimes very hard.
"Physiology is all just propaganda and lies... all waiting to be disproven by the next study."
"I'm not a real doctor; But I am a real worm; I am an actual worm." - TMBG

Magellan3000
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by Magellan3000

Agreed it has been discussed ad nauseum, but IMHO it hasn't been discussed effectively. The most ferocious, antagonistic, unprofessional, uncivil arguments posted against their use are, invariably, by people who have no direct experience of them whatsoever. Worse, these people typically post the Coyle 1991 study as the "proof" that it doesn't work. I guess they think that citing a peer-reviewed study settles the matter or makes them seem knowledgable. Yet anyone who has actually read the study (I did the other night thanks to davinci), can see glaring problems and unanswered questions I noted above. Yet they will parrot the study as if it settles the matter.

In the field I work in (system development) a seminal paper was published in 1970. The entire field was subsequently affected not by what the paper actually said, but by how it was misinterpreted. The misinterpretation was subsequently parroted around the industry for decades. Consequent industry losses attributed to this misinterpretation ran into tens of billions of dollars. Hearing this, I simply couldn't believe it. So I got a copy of the paper and actually read it. Incredibly, anyone who read it through the 3rd page couldn't possibly have misinterpreted the author's conclusion. Citing the Coyle study is not as bad as this example, but IMHO it is plenty problematic.

Your comments about the 'body as system' resonate with me....

For me, the 'system' is the athlete + his protocols for training, nutrition and recovery. The system (athlete) objective is -at least in my case- to complete a long course triathlon as quickly as possible. At any given moment in time, the system's performance is limited by a single constraint. It might be cardiac output, local mitochondrial density, local capillarization, ability to recover, a Central Governor, etc. Better system performance (triathlon finish time) can only be achieved by relieving the system constraint. Once it is relieved, another system constraint will emerge and must then be addressed. As if this is not complex enough, many of the affected muscle groups have to be used in 2 or 3 events... and for very long periods of time. How many peer-reviewed studies of this unique combination of circumstances have been done? Has the fundamental question of 'what causes fatigue in long course competitions' been settled? No so far as I know. In the face of all this complexity it seems nuts to say 'there is a one, true way to prepare'.

The ideas behind Sweet Spot Training tacitly acknowledge that the system constraint in many types of bike racing in unknown and possibly unknowable. SST approach says 'We dunno which of the many required adaptations are the system constraint, but if you follow this protocol, the likely constraints will be relieved at a significant rate'. Many -myself included- seem to find this ambiguity acceptable and worth pursuing. But for some reason, training -while cycling- the hip flexors and hamstrings (both used extensively in running) to undergo these exact same adaptations... 'can't possibly be beneficial' to improve long course triathlon performance?!?!?!?!? It is as if they are saying 'cross training is not effective'. Nonsense.

I'll check out the Jim Martin study. Thanks.

Tapeworm wrote:Whilst it is good you're looking into all of this it has all been discussed ad naseum by many different people who have a great deal of knowledge of such things.

And it simply come down to this, out of all the studies done to date there has been no demonstrable benefit to using powercranks or single leg drills. The closest thing to any benefit by single leg drills are those which use a counterweight on the opposite crank arm - they showed a clear improvement to the oxidative capacity if the muscles HOWEVER this still didn't yield a performance benefit.

Also the counterweight drills show clearly how unessecary any "unweighting" of the pedal really is.

Further studies by Jim Martin (using the Coyle study as a reference) showed that actually a lot of elite riders produced more negative torque than amateurs and that this negative torque was in line with the expected weight of the leg.

One aspect people seem to fail to grasp is that the body is a system. To produce power to propel the bike forward you cannot magically bypass the limitation of the body as a whole. Thus by suddenly using slightly different muscles you cannot create more power than you are capable of. Cardiovascular, thermal, mitochondrial etc are all parts of the system. If you want to use powercranks to pedal then go ahead but you can't suddenly get more power because of it.

Whilst there are hints and possibilities that you may get a few extra watts from weight training, drinking beetroot juice or inertia loaded single legs drills at the end of the day the clearest and proven way to improve is to ride. A lot. Sometimes very hard.

WEG65
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by WEG65

Hi everyone

I own PCs - I have had them for about two years

I commute to work everyday and use them 2 x 30 minutes each day

If I take a week off it is hard to ride them again (in the winter I have a second bike with studded tires, and I prefer not to ride them in the rain because the seals are poor)

I am not convinced that they have changed my fitness/cycling performance

My cycling has improved, but I ride more now and follow the Friel training plan

They do seem to help core strength

I see that there was a recent abstract on PubMed about this issue but wasn't able to link out to the paper (see abstract below)

I am not sure if I will keep them on or take them off

For the price, a used computrainer would be a much better buy




Cycling efficiency and performance following short-term training using uncoupled cranks.
Williams AD, Raj IS, Stucas KL, Fell JW, Dickenson D, Gregory JR.

School of Human Life Sciences, University of Tasmania, Australia.
Abstract
OBJECTIVES: Uncoupled cycling cranks are designed to remove the ability of one leg to assist the other during the cycling action. It has been suggested that training with this type of crank can increase mechanical efficiency. However, whether these improvements can confer performance enhancement in already well-trained cyclists has not been reported.

METHOD: Fourteen well-trained cyclists (13 males, 1 female; 32.4 +/- 8.8 y; 74.5 +/- 10.3 kg; Vo2max 60.6 +/- 5.5 mL.kg-1.min-1; mean +/- SD) participated in this study. Participants were randomized to training on a stationary bicycle using either an uncoupled (n = 7) or traditional crank (n = 7) system. Training involved 1-h sessions, 3 days per week for 6 weeks, and at a heart rate equivalent to 70% of peak power output (PPO) substituted into the training schedule in place of other training. Vo2max, lactate threshold, gross efficiency, and cycling performance were measured before and following the training intervention. Pre- and posttesting was conducted using traditional cranks.

RESULTS: No differences were observed between the groups for changes in Vo2max, lactate threshold, gross efficiency, or average power maintained during a 30-minute time trial.

CONCLUSION: Our results indicate that 6 weeks (18 sessions) of training using an uncoupled crank system does not result in changes in any physiological or performance measures in well-trained cyclists.

Magellan3000
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by Magellan3000

Hi everyone. An update:

I ran the Marine Corps Marathon on 31-Oct-2010. My preparation for that marathon was a structured 12-week plan with weekly loading varying between 35 and 50 miles.

Over the 4 months since that marathon, I have run a grand total of 3 times, for a grand total 13 miles. My pace & HR remains identical to what it was at any point during my marathon training. Aside from this pathetically little running volume, the only training I do is structured bike training (exclusively with PC's) and sporadic master's swimming workouts.

Where's the study showing cross-training doesn't work? Where's the study showing my pace & HR are not what I read with my own eyes an hour ago?

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Tapeworm
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by Tapeworm

12 weeks is not a marathon training plan. It's a warm up.

You would have to compare apples to apples, ie: do one marathon with one system of training then do another with another form of training.

Plenty of studies in this vein if you look for them.

Unfortunately specificity still reigns supreme. Ever wonder why multi-sport athletes are not as good in a discipline as those devoted to that one sport?
"Physiology is all just propaganda and lies... all waiting to be disproven by the next study."
"I'm not a real doctor; But I am a real worm; I am an actual worm." - TMBG

Magellan3000
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by Magellan3000

Are you saying cross-training does not work or does not work for multi-sport athletes?

Tapeworm wrote:12 weeks is not a marathon training plan. It's a warm up.

You would have to compare apples to apples, ie: do one marathon with one system of training then do another with another form of training.

Plenty of studies in this vein if you look for them.

Unfortunately specificity still reigns supreme. Ever wonder why multi-sport athletes are not as good in a discipline as those devoted to that one sport?

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Tapeworm
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by Tapeworm

Magellan3000 wrote:Are you saying cross-training does not work or does not work for multi-sport athletes?


Yes.
"Physiology is all just propaganda and lies... all waiting to be disproven by the next study."
"I'm not a real doctor; But I am a real worm; I am an actual worm." - TMBG

Magellan3000
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Joined: Tue Mar 01, 2011 7:41 pm

by Magellan3000

Tapeworm wrote:
Magellan3000 wrote:Are you saying cross-training does not work or does not work for multi-sport athletes?


Yes.


Do you actually do any endurance sports, or do you just talk about them?

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Tapeworm
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by Tapeworm

Wow, that comment nearly had my 3rd pack of chips and 6th beer all over the screen, I would have got up in anger but 167kgs don't move easily.
"Physiology is all just propaganda and lies... all waiting to be disproven by the next study."
"I'm not a real doctor; But I am a real worm; I am an actual worm." - TMBG

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devinci
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by devinci

:popcorn:

Magellan3000

Tapeworm is such a fatty, clydesdale.

cross-training does not work for singled discipline endurance athlete. You could classify it in the "better then nothing" category but it wont improve your performance in the discipline you compete in. The fact is cross-training goes against one of the most important basic training principle: specificity.

You want to be good at riding your bike? Ride your bike hard, in lots of different ways, get some proper rest, oh, and used regular cranks.

Magellan3000
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Joined: Tue Mar 01, 2011 7:41 pm

by Magellan3000

@Tapeworm, I (obviously) meant it as a joke and hope you took it that way.

I remain amazed that anyone can think cross training isn't effective, at least for multi-sport athletes. In the past I've gotten some good running performances doing almost no running, but lots of cycling and swimming. Maybe I picked good parents.

Greg LeMond did cross country in the off season his whole career. It worked for him. Mark Allen credited his remarkable IM run performances to his bike training. Similarly, Gordo Bryn says 'If you are fading on the run, you likely have a cycling limiter'.

Tonight I'll be swimming all four strokes, even though I'll only, ever, swim crawl in a race. My muscles, mitochondria and capillary beds don't know the difference... please don't tell them!

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